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stringlengths 24
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stringclasses 5
values | feature_version
stringclasses 2
values | input_question
stringlengths 1
1.24k
⌀ | input_code
stringlengths 2
18.5k
⌀ | input_intention
stringlengths 1
2.48k
⌀ | input_task_description
stringlengths 18
3.32k
⌀ |
|---|---|---|---|---|---|---|---|
63c648ea5f004bf4898d00e9 | 2023-02-09T22:03:50.679Z | Help Fix Code | v1 | null | struct pixel **read_pixel_array(FILE *image, int pixel_array_offset, int width, int height) {
struct pixel **px = malloc(sizeof(struct pixel *) * height);
for (int i = 0; i < height; i++) {
px[i] = malloc(sizeof(struct pixel) * width);
px[i] = fseek(image, pixel_array_offset, SEEK_SET);
}
return px;
} | 1. First, allocate space for m `struct pixel *` values, where m is the height of the image. Each pointer will eventually point to one row of pixel data. 2. For each pointer you just allocated, initialize it to point to heap-allocated space for an entire row of pixel data. 3. Use the given file and pixel_array_offset to initialize the actual struct pixel values. Assume that `sizeof(struct pixel) == 3`, which is consistent with the bitmap file format. NOTE: We've tested this assumption on the Teaching Lab machines, but if you're trying to work on your own computer, we strongly recommend checking this assumption! 4. Return the address of the first `struct pixel *` you initialized. | null |
63c648ea5f004bf4898d00e9 | 2023-02-09T22:16:35.120Z | Help Write Code | v1 | null | null | null | Read in the location of the pixel array, the image width, and the image height in the given bitmap file. |
63c648ea5f004bf4898d00e9 | 2023-02-09T22:17:30.381Z | Help Fix Code | v1 | null | void read_bitmap_metadata(FILE *image, int *pixel_array_offset, int *width, int *height) {
fseek(image, 10, SEEK_SET);
fread(pixel_array_offset, sizeof(int), 1, image);
fseek(image, 18, SEEK_SET);
fread(width, sizeof(int), 1, image);
fseek(image, 22, SEEK_SET);
fread(height, sizeof(int), 1, image);
} | Read in the location of the pixel array, the image width, and the image height in the given bitmap file. | null |
63c648ea5f004bf4898d00e9 | 2023-02-09T22:19:36.441Z | Help Fix Code | v1 | null | struct pixel **read_pixel_array(FILE *image, int pixel_array_offset, int width, int height) {
struct pixel **px = malloc(sizeof(struct pixel *) * height);
for (int i = 0; i < height; i++) {
fseek(image, pixel_array_offset, SEEK_SET);
fread(px[i], sizeof(struct pixel), width, image);
}
return px;
} | 1. First, allocate space for m `struct pixel *` values, where m is the height of the image. Each pointer will eventually point to one row of pixel data. 2. For each pointer you just allocated, initialize it to point to heap-allocated space for an entire row of pixel data. 3. Use the given file and pixel_array_offset to initialize the actual struct pixel values. Assume that `sizeof(struct pixel) == 3`, which is consistent with the bitmap file format. NOTE: We've tested this assumption on the Teaching Lab machines, but if you're trying to work on your own computer, we strongly recommend checking this assumption! 4. Return the address of the first `struct pixel *` you initialized. | null |
63c648ea5f004bf4898d00e9 | 2023-02-09T22:21:09.741Z | Help Fix Code | v1 | null | struct pixel **read_pixel_array(FILE *image, int pixel_array_offset, int width, int height) {
struct pixel **px = malloc(sizeof(struct pixel *) * height);
for (int i = 0; i < height; i++) {
px[i] = malloc(sizeof(struct pixel) * width);
fseek(image, pixel_array_offset, SEEK_SET);
fread(px[i], sizeof(struct pixel), width, image);
}
return px;
} | 1. First, allocate space for m `struct pixel *` values, where m is the height of the image. Each pointer will eventually point to one row of pixel data. 2. For each pointer you just allocated, initialize it to point to heap-allocated space for an entire row of pixel data. 3. Use the given file and pixel_array_offset to initialize the actual struct pixel values. Assume that `sizeof(struct pixel) == 3`, which is consistent with the bitmap file format. NOTE: We've tested this assumption on the Teaching Lab machines, but if you're trying to work on your own computer, we strongly recommend checking this assumption! 4. Return the address of the first `struct pixel *` you initialized.
| null |
63c648ea5f004bf4898d00e9 | 2023-02-09T22:23:21.262Z | Help Fix Code | v1 | null | struct pixel **read_pixel_array(FILE *image, int pixel_array_offset, int width, int height) {
struct pixel **px = malloc(sizeof(struct pixel *) * height);
for (int i = 0; i < height; i++) {
*px[i] = malloc(sizeof(struct pixel) * width);
fseek(image, pixel_array_offset, SEEK_SET);
fread(px[i], sizeof(struct pixel), width, image);
}
return px;
} | 1. First, allocate space for m `struct pixel *` values, where m is the height of the image. Each pointer will eventually point to one row of pixel data. 2. For each pointer you just allocated, initialize it to point to heap-allocated space for an entire row of pixel data. 3. Use the given file and pixel_array_offset to initialize the actual struct pixel values. Assume that `sizeof(struct pixel) == 3`, which is consistent with the bitmap file format. NOTE: We've tested this assumption on the Teaching Lab machines, but if you're trying to work on your own computer, we strongly recommend checking this assumption! 4. Return the address of the first `struct pixel *` you initialized. | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T15:27:35.356Z | Help Write Code | v1 | null | null | null | Create a new user with the given name. Insert it at the tail of the list of users whose head is pointed to by *user_ptr_add.
Return:
- 0 if successful
- 1 if a user by this name already exists in this list
- 2 if the given name cannot fit in the 'name' array (don't forget about the null terminator) |
63c648ea5f004bf4898d00e9 | 2023-02-15T15:49:29.967Z | Help Fix Code | v1 | null | int create_user(const char *name, User **user_ptr_add) {
if (strlen(name) > MAX_NAME - 1) {
return 2;
}
User curr = **user_ptr_add;
while (curr.next != NULL) {
if(strcmp(curr.name, name) == 0) {
return 1;
}
curr = *curr.next;
}
User user;
strcpy(user.name, name);
curr.next = &user;
return 0;
} | Create a new user with the given name. Insert it at the tail of the list of users whose head is pointed to by *user_ptr_add. Return: - 0 if successful - 1 if a user by this name already exists in this list - 2 if the given name cannot fit in the 'name' array (don't forget about the null terminator) | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T15:54:29.128Z | Help Fix Code | v1 | null | User *find_user(const char *name, const User *head) {
User curr = *head;
while (curr.next != NULL) {
if(strcmp(curr.name, name) == 0) {
return &curr;
}
curr = *curr.next;
}
return NULL;
} | Return a pointer to the user with this name in the list starting with head. Return NULL if no such user exists.
NOTE: You'll likely need to cast a (const User *) to a (User *) to satisfy the prototype without warnings. | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T15:59:17.617Z | Help Fix Code | v1 | null | User *find_user(const char *name, const User *head) {
User *curr = (User *) head;
while ((*curr).next != NULL) {
if(strcmp((*curr).name, name) == 0) {
return curr;
}
curr = (*curr).next;
}
return NULL;
} | Return a pointer to the user with this name in the list starting with head. Return NULL if no such user exists. NOTE: You'll likely need to cast a (const User *) to a (User *) to satisfy the prototype without warnings. | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T16:59:14.520Z | Help Fix Code | v1 | null | int make_friends(const char *name1, const char *name2, User *head) {
if (find_user(name1, head) == NULL || find_user(name2, head) == NULL) {
return 4;
} else if (strcmp(name1, name2) == 0) {
return 3;
}
User *user1 = find_user(name1, head);
User *user1_friends[MAX_FRIENDS] = user1->friends;
User *user2 = find_user(name2, head);
User *user2_friends[MAX_FRIENDS] = user2->friends;
for (int i = 0; i < MAX_FRIENDS; i++) {
if (user1_friends[i] == user2) {
return 1;
} else if (user2_friends[i] == user1) {
return 1;
}
}
if (user1_friends[MAX_FRIENDS - 1] != NULL || user2_friends[MAX_FRIENDS - 1] != NULL) {
return 2;
} else {
int i = 0;
while (user1_friends[i] != NULL) {
i++;
}
user1_friends[i] = user2;
int j = 0;
while (user2_friends[j] != NULL) {
j++;
}
user2_friends[j] = user1;
}
return 0;
} | Make two users friends with each other. This is symmetric - a pointer to each user must be stored in the 'friends' array of the other.
New friends must be added in the first empty spot in the 'friends' array.
Return:
- 0 on success.
- 1 if the two users are already friends.
- 2 if the users are not already friends, but at least one already has MAX_FRIENDS friends.
- 3 if the same user is passed in twice.
- 4 if at least one user does not exist.
Do not modify either user if the result is a failure. NOTE: If multiple errors apply, return the *largest* error code that applies. | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T20:43:23.760Z | General Question | v1 | how to print out variable with type time_t | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T21:13:07.942Z | General Question | v1 | how to use time function to find the current time | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T22:20:16.803Z | Help Fix Code | v1 | null | int create_user(const char *name, User **user_ptr_add) {
if (strlen(name) > MAX_NAME - 1) {
return 2;
}
if (*user_ptr_add == NULL) {
User user;
strcpy(user.name, name);
*user_ptr_add = &user;
return 0;
}
User *curr = *user_ptr_add;
while (curr->next != NULL) {
if(strcmp(curr->name, name) == 0) {
return 1;
}
curr = curr->next;
}
User user;
strcpy(user.name, name);
curr->next = &user;
return 0;
} | Create a new user with the given name. Insert it at the tail of the list
* of users whose head is pointed to by *user_ptr_add.
*
* Return:
* - 0 if successful
* - 1 if a user by this name already exists in this list
* - 2 if the given name cannot fit in the 'name' array
* (don't forget about the null terminator) | null |
63c648ea5f004bf4898d00e9 | 2023-02-15T22:29:14.275Z | Help Fix Code | v1 | null | int create_user(const char *name, User **user_ptr_add) {
if (strlen(name) > MAX_NAME - 1) {
return 2;
}
if (*user_ptr_add == NULL) {
User *user = malloc(sizeof(User));
strcpy(user->name, name);
*user_ptr_add = user;
return 0;
}
User *curr = *user_ptr_add;
while (curr->next != NULL) {
if(strcmp(curr->name, name) == 0) {
return 1;
}
curr = curr->next;
}
User *user = malloc(sizeof(User));
strcpy(user->name, name);
curr->next = user;
return 0;
} | Create a new user with the given name. Insert it at the tail of the list * of users whose head is pointed to by *user_ptr_add. * * Return: * - 0 if successful * - 1 if a user by this name already exists in this list * - 2 if the given name cannot fit in the 'name' array * (don't forget about the null terminator) | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T00:59:21.213Z | Help Fix Code | v1 | null | User *find_user(const char *name, const User *head) {
User *curr = (User *) head;
if (curr != NULL) {
while (curr->next != NULL) {
if(strcmp(curr->name, name) == 0) {
return curr;
}
curr = curr->next;
}
if(strcmp(curr->name, name) == 0) {
return curr;
}
}
return NULL;
} | Return a pointer to the user with this name in
* the list starting with head. Return NULL if no such user exists.
*
* NOTE: You'll likely need to cast a (const User *) to a (User *)
* to satisfy the prototype without warnings. | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:03:58.671Z | Help Fix Code | v1 | null | User *find_user(const char *name, const User *head) {
User *curr = (User *) head;
while (curr != NULL) {
if(strcmp(curr->name, name) == 0) {
return curr;
}
curr = curr->next;
}
return NULL;
} | Return a pointer to the user with this name in * the list starting with head. Return NULL if no such user exists. * * NOTE: You'll likely need to cast a (const User *) to a (User *) * to satisfy the prototype without warnings. | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:04:35.651Z | Help Fix Code | v1 | null | void list_users(const User *curr) {
printf("User List\n");
while (curr != NULL){
printf("%s\n", curr->name);
curr = curr->next;
}
} | Print the usernames of all users in the list starting at curr.
* Names should be printed to standard output, one per line. | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:05:13.745Z | Help Fix Code | v1 | null | int update_pic(User *user, const char *filename) {
if (strlen(filename) > MAX_NAME - 1) {
return 2;
} else if (fopen(filename, "r") == NULL) {
return 1;
} else {
strcpy(user->profile_pic, filename);
return 0;
}
} | Change the filename for the profile pic of the given user.
*
* Return:
* - 0 on success.
* - 1 if the file does not exist or cannot be opened.
* - 2 if the filename is too long. | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:07:29.464Z | Help Fix Code | v1 | null | int make_friends(const char *name1, const char *name2, User *head) {
if (find_user(name1, head) == NULL || find_user(name2, head) == NULL) {
return 4;
} else if (strcmp(name1, name2) == 0) {
return 3;
}
User *user1 = find_user(name1, head);
User *user2 = find_user(name2, head);
for (int i = 0; i < MAX_FRIENDS; i++) {
if (user1->friends[i] == user2) {
return 1;
} else if (user2->friends[i] == user1) {
return 1;
}
}
if (user1->friends[MAX_FRIENDS - 1] != NULL || user2->friends[MAX_FRIENDS - 1] != NULL) {
return 2;
} else {
int i = 0;
while (user1->friends[i] != NULL) {
i++;
}
user1->friends[i] = user2;
int j = 0;
while (user2->friends[j] != NULL) {
j++;
}
user2->friends[j] = user1;
}
return 0;
} | Make two users friends with each other. This is symmetric - a pointer to
* each user must be stored in the 'friends' array of the other.
*
* New friends must be added in the first empty spot in the 'friends' array.
*
* Return:
* - 0 on success.
* - 1 if the two users are already friends.
* - 2 if the users are not already friends, but at least one already has
* MAX_FRIENDS friends.
* - 3 if the same user is passed in twice.
* - 4 if at least one user does not exist.
*
* Do not modify either user if the result is a failure.
* NOTE: If multiple errors apply, return the *largest* error code that applies. | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:32:54.537Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) {
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) {
Post *post = NULL;
strcpy(post->author, author->name);
strcpy(post->contents, contents);
*post->date = time(NULL);
if (target->first_post != NULL) {
Post *temp = target->first_post;
post->next = temp;
}
target->first_post = post;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user,
* containing the given contents, IF the users are friends.
*
* Insert the new post at the *front* of the user's list of posts.
*
* 'contents' is a pointer to heap-allocated memory - you do not need
* to allocate more memory to store the contents of the post.
*
* Return:
* - 0 on success
* - 1 if users exist but are not friends
* - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:34:03.119Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) {
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) {
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
*post->date = time(NULL);
if (target->first_post != NULL) {
Post *temp = target->first_post;
post->next = temp;
}
target->first_post = post;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user, * containing the given contents, IF the users are friends. * * Insert the new post at the *front* of the user's list of posts. * * 'contents' is a pointer to heap-allocated memory - you do not need * to allocate more memory to store the contents of the post. * * Return: * - 0 on success * - 1 if users exist but are not friends * - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:34:45.868Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) {
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) {
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
post->date = time(NULL);
if (target->first_post != NULL) {
Post *temp = target->first_post;
post->next = temp;
}
target->first_post = post;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user, * containing the given contents, IF the users are friends. * * Insert the new post at the *front* of the user's list of posts. * * 'contents' is a pointer to heap-allocated memory - you do not need * to allocate more memory to store the contents of the post. * * Return: * - 0 on success * - 1 if users exist but are not friends * - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:40:59.801Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) {
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) {
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
*post->date = time(NULL);
post->next = target->first_post;
target->first_post = post;
return 0;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user,
* containing the given contents, IF the users are friends.
*
* Insert the new post at the *front* of the user's list of posts.
*
* 'contents' is a pointer to heap-allocated memory - you do not need
* to allocate more memory to store the contents of the post.
*
* Return:
* - 0 on success
* - 1 if users exist but are not friends
* - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:41:33.165Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) {
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) {
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
post->date = time(NULL);
post->next = target->first_post;
target->first_post = post;
return 0;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user,
* containing the given contents, IF the users are friends.
*
* Insert the new post at the *front* of the user's list of posts.
*
* 'contents' is a pointer to heap-allocated memory - you do not need
* to allocate more memory to store the contents of the post.
*
* Return:
* - 0 on success
* - 1 if users exist but are not friends
* - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:42:35.209Z | Question from Code | v1 | why does it have Segmentation fault: 11 | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) {
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) {
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
post->date = time(NULL);
post->next = target->first_post;
target->first_post = post;
return 0;
}
}
return 1;
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T01:55:16.968Z | General Question | v1 | what is a Segmentation fault:11 ? how can i deal with it? | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T02:02:48.584Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) {
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) {
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
*post->date = time(NULL);
post->next = target->first_post;
target->first_post = post;
return 0;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user,
* containing the given contents, IF the users are friends.
*
* Insert the new post at the *front* of the user's list of posts.
*
* 'contents' is a pointer to heap-allocated memory - you do not need
* to allocate more memory to store the contents of the post.
*
* Return:
* - 0 on success
* - 1 if users exist but are not friends
* - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T02:26:07.499Z | Help Fix Code | v1 | null | int delete_user(const char *name, User **user_ptr_del) {
// check whether the user with this name exist or not
User *user = find_user(name, *user_ptr_del);
if (user == NULL) {
return 1;
}
// unlink this user with others
User *curr = *user_ptr_del;
if (strcmp(curr->name, name) == 0) {
curr->next = NULL;
} else {
while (curr->next != NULL) {
if (strcmp(curr->next->name, name) == 0) {
curr->next = curr->next->next;
}
curr = curr->next;
}
}
// remove this user from any friend's lists
for (int i = 0; i < MAX_FRIENDS; i++) {
if (user->friends[i] != NULL) {
for (int j = 0; j < MAX_FRIENDS; j++) {
if (user->friends[i]->friends[j] == user) {
user->friends[i]->friends[j] = NULL;
}
}
}
}
// free all heap memory that was allocated
Post *post = user->first_post;
while (post != NULL) {
free(post->contents);
post = post->next;
free(post);
}
free(user);
return 0;
} | * From the list pointed to by *user_ptr_del, delete the user
* with the given name.
* Remove the deleted user from any lists of friends.
*
* Return:
* - 0 on success.
* - 1 if a user with this name does not exist. | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T03:04:49.414Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) { //check whether either User pointer is NULL
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) { // check whether they are friends, then add posts to them
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
*post->date = time(NULL);
post->next = target->first_post;
target->first_post = post;
return 0;
}
}
return 1;
}
| Make a new post from 'author' to the 'target' user,
* containing the given contents, IF the users are friends.
*
* Insert the new post at the *front* of the user's list of posts.
*
* 'contents' is a pointer to heap-allocated memory - you do not need
* to allocate more memory to store the contents of the post.
*
* Return:
* - 0 on success
* - 1 if users exist but are not friends
* - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T03:10:27.133Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) { //check whether either User pointer is NULL
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) { // check whether they are friends, then add posts to them
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
strcpy(post->contents, contents);
post->date = malloc(sizeof(time_t));
*post->date = time(NULL);
post->next = target->first_post;
target->first_post = post;
return 0;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user, * containing the given contents, IF the users are friends. * * Insert the new post at the *front* of the user's list of posts. * * 'contents' is a pointer to heap-allocated memory - you do not need * to allocate more memory to store the contents of the post. * * Return: * - 0 on success * - 1 if users exist but are not friends * - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-02-16T03:12:59.020Z | Help Fix Code | v1 | null | int make_post(const User *author, User *target, char *contents) {
if (author == NULL || target == NULL) { //check whether either User pointer is NULL
return 2;
}
for (int i = 0; i < MAX_FRIENDS; i++) {
if (author->friends[i] == target) { // check whether they are friends, then add posts to them
Post *post = malloc(sizeof(Post));
strcpy(post->author, author->name);
post->contents, contents;
post->date = malloc(sizeof(time_t));
*post->date = time(NULL);
post->next = target->first_post;
target->first_post = post;
return 0;
}
}
return 1;
} | Make a new post from 'author' to the 'target' user, * containing the given contents, IF the users are friends. * * Insert the new post at the *front* of the user's list of posts. * * 'contents' is a pointer to heap-allocated memory - you do not need * to allocate more memory to store the contents of the post. * * Return: * - 0 on success * - 1 if users exist but are not friends * - 2 if either User pointer is NULL | null |
63c648ea5f004bf4898d00e9 | 2023-03-02T22:18:32.431Z | General Question | v1 | how to use wait() | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-02T22:28:31.891Z | Question from Code | v1 | How many processes are created, including the original parent, when forkloop is called with 2, 3, and 4 as arguments? n arguments? | #include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
int main(int argc, char **argv) {
if (argc != 2) {
fprintf(stderr, "Usage: forkloop <iterations>\n");
exit(1);
}
int iterations = strtol(argv[1], NULL, 10);
for (int i = 0; i < iterations; i++) {
int n = fork();
if (n < 0) {
perror("fork");
exit(1);
}
else if (n > 0) {
int status;
wait(&status);
}
printf("ppid = %d, pid = %d, i = %d\n", getppid(), getpid(), i);
}
return 0;
}
| null | null |
63c648ea5f004bf4898d00e9 | 2023-03-02T22:53:08.847Z | Question from Code | v1 | How many processes are created, including the original parent, when forkloop is called with 2, 3, and 4 as arguments? n arguments? | #include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
int main(int argc, char **argv) {
if (argc != 2) {
fprintf(stderr, "Usage: forkloop <iterations>\n");
exit(1);
}
int iterations = strtol(argv[1], NULL, 10);
for (int i = 0; i < iterations; i++) {
int n = fork();
if (n < 0) {
perror("fork");
exit(1);
}
printf("ppid = %d, pid = %d, i = %d\n", getppid(), getpid(), i);
}
return 0;
}
| null | null |
63c648ea5f004bf4898d00e9 | 2023-03-02T23:07:55.451Z | Question from Code | v1 | Create a copy of forkloop.c called parentcreates.c. In the new file, modify the program so that the new children do not create additional processes. Only the original parent calls fork. Keep the printf call for all processes. The resulting diagram will look something like the following when parentcreates 3 is run. In this case, the parent process creates 3 child processes. Note that the child process ids will not necessarily be in sequence. | #include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
int main(int argc, char **argv) {
if (argc != 2) {
fprintf(stderr, "Usage: forkloop <iterations>\n");
exit(1);
}
int iterations = strtol(argv[1], NULL, 10);
for (int i = 0; i < iterations; i++) {
int n = fork();
if (n < 0) {
perror("fork");
exit(1);
}
printf("ppid = %d, pid = %d, i = %d\n", getppid(), getpid(), i);
}
return 0;
}
| null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T18:03:38.669Z | General Question | v1 | how to use exec and execl | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T18:06:18.182Z | General Question | v1 | how to use dup2 | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T18:10:28.610Z | General Question | v1 | what the difference between dup, pipe and fork | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T18:11:11.913Z | General Question | v1 | what the difference between dup2, pipe, fork and execl | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T18:13:34.124Z | Explain Code | v1 | null | if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T18:29:46.936Z | General Question | v1 | how to prints a message to stdout | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T18:38:58.428Z | General Question | v1 | how to get exit code when calling execl | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T19:02:41.954Z | Help Fix Code | v1 | null | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define MAXLINE 256
#define SUCCESS "Password verified\n"
#define INVALID "Invalid password\n"
#define NO_USER "No such user\n"
int main(void) {
char user_id[MAXLINE];
char password[MAXLINE];
/* The user will type in a user name on one line followed by a password
on the next.
DO NOT add any prompts. The only output of this program will be one
of the messages defined above.
Please read the comments in validate carefully
*/
if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
if(fgets(password, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
// TODO
int n = fork();
if (n < 0) {
perror("fork");
exit(1);
} else if (n == 0) { // child process
execl("./validate", "validate", user_id, password, NULL);
perror("execl");
exit(1);
} else { // parent process
int status;
pid_t child_pid = wait(&status);
if (child_pid == -1) {
perror("wait");
exit(1);
}
if (WIFEXITED(status)) {
int child_status = WEXITSTATUS(status);
if (child_status == 0) {
printf(SUCCESS);
} else if (child_status == 2) {
printf(INVALID);
} else if (child_status == 3) {
printf(NO_USER);
}
}
}
return 0;
} | Your task is to complete checkpasswd.c, which reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful.
Your program should use the exit status of the validate program to determine which of the three following messages to print:
"Password verified" if the user id and password match.
"Invalid password" if the user id exists, but the password does not match.
"No such user" if the user id is not recognized
The exact messages are given in the starter code as defined constants.
The only case that should be handled directly in checkpasswd is the case where either the userid or password are too long. This is to prevent sending the wrong number of bytes to validate.
Note that in the given password file pass.txt, the "killerwhales:swim" has a user id that is too large, and "monkeys:eatcoconuts" has a password that is too long. The examples are expected to fail, but the other cases should work correctly. | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T19:04:45.152Z | Help Write Code | v1 | null | null | null | Your task is to complete checkpasswd.c, which reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful.
Your program should use the exit status of the validate program to determine which of the three following messages to print:
"Password verified" if the user id and password match.
"Invalid password" if the user id exists, but the password does not match.
"No such user" if the user id is not recognized
The exact messages are given in the starter code as defined constants.
The only case that should be handled directly in checkpasswd is the case where either the userid or password are too long. This is to prevent sending the wrong number of bytes to validate.
Note that in the given password file pass.txt, the "killerwhales:swim" has a user id that is too large, and "monkeys:eatcoconuts" has a password that is too long. The examples are expected to fail, but the other cases should work correctly. |
63c648ea5f004bf4898d00e9 | 2023-03-08T19:33:48.027Z | Help Fix Code | v1 | null | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define MAXLINE 256
#define MAX_PASSWORD 10
#define SUCCESS "Password verified\n"
#define INVALID "Invalid password\n"
#define NO_USER "No such user\n"
int main(void) {
char user_id[MAXLINE];
char password[MAXLINE];
/* The user will type in a user name on one line followed by a password
on the next.
DO NOT add any prompts. The only output of this program will be one
of the messages defined above.
Please read the comments in validate carefully
*/
if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
if(fgets(password, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
// TODO
// check length of user id and password
if (strlen(user_id) > MAX_PASSWORD || strlen(password) > MAX_PASSWORD) {
printf("The user id or password are too long");
exit(1);
}
//create pipe
int pipefd[2];
pipe(pipefd);
int read_end = pipefd[0];
int write_end = pipefd[1];
int n = fork(); //fork
if (n < 0) {
perror("fork");
exit(1);
} else if (n == 0) { // child process
close(read_end);
dup2(1, write_end);
execl("./validate", "validate", user_id, password, NULL);
write(write_end, stdout, sizeof(int));
close(write_end);
perror("execl");
exit(1);
} else { // parent process
close(write_end);
int status;
pid_t child_pid = wait(&status);
if (child_pid == -1) {
perror("wait");
exit(1);
}
int child_status;
if (WIFEXITED(status)) {
close(write_end);
read(read_end, &child_status, sizeof(int));
close(read_end);
// int child_status = WEXITSTATUS(status);
if (child_status == 0) {
printf(SUCCESS);
} else if (child_status == 2) {
printf(INVALID);
} else if (child_status == 3) {
printf(NO_USER);
}
}
}
return 0;
}
| Your task is to complete checkpasswd.c, which reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful. Your program should use the exit status of the validate program to determine which of the three following messages to print: "Password verified" if the user id and password match. "Invalid password" if the user id exists, but the password does not match. "No such user" if the user id is not recognized The exact messages are given in the starter code as defined constants. The only case that should be handled directly in checkpasswd is the case where either the userid or password are too long. This is to prevent sending the wrong number of bytes to validate. Note that in the given password file pass.txt, the "killerwhales:swim" has a user id that is too large, and "monkeys:eatcoconuts" has a password that is too long. The examples are expected to fail, but the other cases should work correctly. | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T19:38:55.015Z | Help Fix Code | v1 | null | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define MAXLINE 256
#define MAX_PASSWORD 10
#define SUCCESS "Password verified\n"
#define INVALID "Invalid password\n"
#define NO_USER "No such user\n"
int main(void) {
char user_id[MAXLINE];
char password[MAXLINE];
/* The user will type in a user name on one line followed by a password
on the next.
DO NOT add any prompts. The only output of this program will be one
of the messages defined above.
Please read the comments in validate carefully
*/
if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
if(fgets(password, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
// TODO
// check length of user id and password
if (strlen(user_id) > MAX_PASSWORD || strlen(password) > MAX_PASSWORD) {
printf("The user id or password are too long");
exit(1);
}
//create pipe
int pipefd[2];
pipe(pipefd);
int read_end = pipefd[0];
int write_end = pipefd[1];
int n = fork(); //fork
if (n < 0) {
perror("fork");
exit(1);
} else if (n == 0) { // child process
close(read_end);
execl("./validate", "validate", user_id, password, NULL);
dup2(1, write_end);
close(write_end);
perror("execl");
exit(1);
} else { // parent process
close(write_end);
int status;
pid_t child_pid = wait(&status);
if (child_pid == -1) {
perror("wait");
exit(1);
}
int child_status;
if (WIFEXITED(status)) {
close(write_end);
// read(read_end, &child_status, sizeof(int));
dup2(1, read_end);
close(read_end);
// int child_status = WEXITSTATUS(status);
if (child_status == 0) {
printf(SUCCESS);
} else if (child_status == 2) {
printf(INVALID);
} else if (child_status == 3) {
printf(NO_USER);
}
}
}
return 0;
}
| Your task is to complete checkpasswd.c, which reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful. Your program should use the exit status of the validate program to determine which of the three following messages to print: "Password verified" if the user id and password match. "Invalid password" if the user id exists, but the password does not match. "No such user" if the user id is not recognized The exact messages are given in the starter code as defined constants. The only case that should be handled directly in checkpasswd is the case where either the userid or password are too long. This is to prevent sending the wrong number of bytes to validate. Note that in the given password file pass.txt, the "killerwhales:swim" has a user id that is too large, and "monkeys:eatcoconuts" has a password that is too long. The examples are expected to fail, but the other cases should work correctly. | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T19:50:46.062Z | Help Fix Code | v1 | null | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define MAXLINE 256
#define MAX_PASSWORD 10
#define SUCCESS "Password verified\n"
#define INVALID "Invalid password\n"
#define NO_USER "No such user\n"
int main(void) {
char user_id[MAXLINE];
char password[MAXLINE];
/* The user will type in a user name on one line followed by a password
on the next.
DO NOT add any prompts. The only output of this program will be one
of the messages defined above.
Please read the comments in validate carefully
*/
if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
if(fgets(password, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
// TODO
// check length of user id and password
if (strlen(user_id) > MAX_PASSWORD || strlen(password) > MAX_PASSWORD) {
printf("The user id or password are too long");
exit(1);
}
//create pipe
int pipefd[2];
if (pipe(pipefd) == -1) {
perror("pipe");
exit(1);
}
int read_end = pipefd[0];
int write_end = pipefd[1];
int n = fork(); //fork
if (n < 0) {
perror("fork");
exit(1);
} else if (n == 0) { // child process
close(read_end);
dup2(write_end, STDOUT_FILENO);
close(write_end);
execl("./validate", "validate", user_id, password, NULL);
perror("execl");
exit(1);
} else { // parent process
close(write_end);
int status;
pid_t child_pid = wait(&status);
if (child_pid == -1) {
perror("wait");
exit(1);
}
if (WIFEXITED(status)) {
int child_status = WEXITSTATUS(status);
if (child_status == 0) {
printf(SUCCESS);
} else if (child_status == 2) {
printf(INVALID);
} else if (child_status == 3) {
printf(NO_USER);
}
}
close(read_end);
}
return 0;
}
| Your task is to complete checkpasswd.c, which reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful. Your program should use the exit status of the validate program to determine which of the three following messages to print: "Password verified" if the user id and password match. "Invalid password" if the user id exists, but the password does not match. "No such user" if the user id is not recognized The exact messages are given in the starter code as defined constants. The only case that should be handled directly in checkpasswd is the case where either the userid or password are too long. This is to prevent sending the wrong number of bytes to validate. Note that in the given password file pass.txt, the "killerwhales:swim" has a user id that is too large, and "monkeys:eatcoconuts" has a password that is too long. The examples are expected to fail, but the other cases should work correctly. | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T19:53:56.259Z | Explain Code | v1 | null | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define MAXLINE 256
#define MAX_PASSWORD 10
#define SUCCESS "Password verified\n"
#define INVALID "Invalid password\n"
#define NO_USER "No such user\n"
int main(void) {
char user_id[MAXLINE];
char password[MAXLINE];
/* The user will type in a user name on one line followed by a password
on the next.
DO NOT add any prompts. The only output of this program will be one
of the messages defined above.
Please read the comments in validate carefully
*/
if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
if(fgets(password, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
// TODO
// check length of user id and password
if (strlen(user_id) > MAX_PASSWORD || strlen(password) > MAX_PASSWORD) {
printf("The user id or password are too long");
exit(1);
}
//create pipe
int pipefd[2];
if (pipe(pipefd) == -1) {
perror("pipe");
exit(1);
}
int read_end = pipefd[0];
int write_end = pipefd[1];
int n = fork(); //fork
if (n < 0) {
perror("fork");
exit(1);
} else if (n == 0) { // child process
close(read_end);
dup2(write_end, STDOUT_FILENO);
close(write_end);
execl("./validate", "validate", user_id, password, NULL);
perror("execl");
exit(1);
} else { // parent process
close(write_end);
int status;
pid_t child_pid = wait(&status);
if (child_pid == -1) {
perror("wait");
exit(1);
}
if (WIFEXITED(status)) {
int child_status = WEXITSTATUS(status);
if (child_status == 0) {
printf(SUCCESS);
} else if (child_status == 2) {
printf(INVALID);
} else if (child_status == 3) {
printf(NO_USER);
}
}
close(read_end);
}
return 0;
}
| null | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T20:38:49.769Z | Help Fix Code | v1 | null | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define MAXLINE 256
#define MAX_PASSWORD 10
#define SUCCESS "Password verified\n"
#define INVALID "Invalid password\n"
#define NO_USER "No such user\n"
int main(void) {
char user_id[MAXLINE];
char password[MAXLINE];
/* The user will type in a user name on one line followed by a password
on the next.
DO NOT add any prompts. The only output of this program will be one
of the messages defined above.
Please read the comments in validate carefully
*/
if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
if(fgets(password, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
// TODO
// check length of user id and password
if (strlen(user_id) > MAX_PASSWORD || strlen(password) > MAX_PASSWORD) {
printf("The user id or password are too long.\n");
exit(1);
}
//create pipe
int pipefd[2];
if (pipe(pipefd) == -1) {
perror("pipe");
exit(1);
}
int read_end = pipefd[0];
int write_end = pipefd[1];
int n = fork(); //fork
if (n < 0) {
perror("fork");
exit(1);
} else if (n == 0) { // child process
close(write_end);
dup2(read_end, STDIN_FILENO);
close(read_end);
execl("./validate", "validate", NULL);
perror("execl");
exit(1);
} else { // parent process
close(read_end);
write(write_end, stdin, sizeof(stdin));
close(write_end);
int status;
pid_t child_pid = wait(&status);
if (child_pid == -1) {
perror("wait");
exit(1);
}
if (WIFEXITED(status)) {
int child_status = WEXITSTATUS(status);
if (child_status == 0) {
printf(SUCCESS);
} else if (child_status == 2) {
printf(INVALID);
} else if (child_status == 3) {
printf(NO_USER);
}
}
}
return 0;
}
| Your task is to complete checkpasswd.c, which reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful. Your program should use the exit status of the validate program to determine which of the three following messages to print: "Password verified" if the user id and password match. "Invalid password" if the user id exists, but the password does not match. "No such user" if the user id is not recognized The exact messages are given in the starter code as defined constants. The only case that should be handled directly in checkpasswd is the case where either the userid or password are too long. This is to prevent sending the wrong number of bytes to validate. Note that in the given password file pass.txt, the "killerwhales:swim" has a user id that is too large, and "monkeys:eatcoconuts" has a password that is too long. The examples are expected to fail, but the other cases should work correctly. | null |
63c648ea5f004bf4898d00e9 | 2023-03-08T20:51:04.604Z | Help Fix Code | v1 | null | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define MAXLINE 256
#define MAX_PASSWORD 10
#define SUCCESS "Password verified\n"
#define INVALID "Invalid password\n"
#define NO_USER "No such user\n"
int main(void) {
char user_id[MAXLINE];
char password[MAXLINE];
/* The user will type in a user name on one line followed by a password
on the next.
DO NOT add any prompts. The only output of this program will be one
of the messages defined above.
Please read the comments in validate carefully
*/
if(fgets(user_id, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
if(fgets(password, MAXLINE, stdin) == NULL) {
perror("fgets");
exit(1);
}
// TODO
// check length of user id and password
if (strlen(user_id) > MAX_PASSWORD || strlen(password) > MAX_PASSWORD) {
printf("The user id or password are too long.\n");
exit(1);
}
//create pipe
int pipefd[2];
if (pipe(pipefd) == -1) {
perror("pipe");
exit(1);
}
int read_end = pipefd[0];
int write_end = pipefd[1];
int n = fork(); //fork
if (n < 0) {
perror("fork");
exit(1);
} else if (n == 0) { // child process
close(write_end);
dup2(read_end, STDIN_FILENO);
close(read_end);
execl("./validate", "validate", NULL);
perror("execl");
exit(1);
} else { // parent process
close(read_end);
write(write_end, user_id, strlen(user_id));
write(write_end, password, strlen(password));
close(write_end);
int status;
pid_t child_pid = wait(&status);
if (child_pid == -1) {
perror("wait");
exit(1);
}
if (WIFEXITED(status)) {
int child_status = WEXITSTATUS(status);
if (child_status == 0) {
printf(SUCCESS);
} else if (child_status == 2) {
printf(INVALID);
} else if (child_status == 3) {
printf(NO_USER);
}
}
}
return 0;
}
| Your task is to complete checkpasswd.c, which reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful. Your program should use the exit status of the validate program to determine which of the three following messages to print: "Password verified" if the user id and password match. "Invalid password" if the user id exists, but the password does not match. "No such user" if the user id is not recognized The exact messages are given in the starter code as defined constants. The only case that should be handled directly in checkpasswd is the case where either the userid or password are too long. This is to prevent sending the wrong number of bytes to validate. Note that in the given password file pass.txt, the "killerwhales:swim" has a user id that is too large, and "monkeys:eatcoconuts" has a password that is too long. The examples are expected to fail, but the other cases should work correctly. | null |
63c648ea5f004bf4898d00e9 | 2023-03-14T00:33:40.593Z | Help Write Code | v2 | null | null | null | /* Read from the open file fp, and create the linked data structure
that represents the Makefile contained in the file.
See the top of pmake.h for the specification of Makefile contents.
*/
Rule *parse_file(FILE *fp) {
// Implement this function and remove the stubbed return statement below.
read(fp);
return NULL;
} |
63c648ea5f004bf4898d00e9 | 2023-03-14T00:34:48.008Z | Help Write Code | v2 | null | null | null | /* Read from the open file fp, and create the linked data structure that represents the Makefile contained in the file. See the top of pmake.h for the specification of Makefile contents. */ Rule *parse_file(FILE *fp) { // Implement this function and remove the stubbed return statement below. return NULL; } |
63c648ea5f004bf4898d00e9 | 2023-03-14T16:51:40.675Z | Explain Code | v2 | null |
int is_comment_or_empty(const char *line) {
for (int i = 0; i < strlen(line); i++) {
if (line[i] == '#') {
return 1;
}
if (line[i] != '\t' && line[i] != ' ') {
return 0;
}
}
return 1;
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-14T18:21:50.954Z | Help Fix Code | v2 | Read from the open file fp, and create the linked data structure
that represents the Makefile contained in the file.
See the top of pmake.h for the specification of Makefile contents. | Rule *parse_file(FILE *fp) {
// Implement this function and remove the stubbed return statement below.
Rule *head_rule, *curr_rule;
char line[MAXLINE];
while (fgets(line, MAXLINE, fp) != NULL) {
// Check if a line of text is a comment or an empty line.
if (is_comment_or_empty(line)) {
continue;
}
// Parse the line.
char *target = strtok(line, " \t\n");
Dependency *dependencies = NULL;
Dependency *curr_dep = NULL;
Action *actions = NULL;
Action *curr_act = NULL;
char *token = strtok(NULL, " \t\n");
// while ((token = strtok(NULL, " \t\n")) != NULL) {
if (strcmp(token, ":") == 0) {
// Parse the dependency
while ((token = strtok(NULL, " \t\n")) != NULL) {
Dependency *dep = malloc(sizeof(Dependency));
if (dependencies == NULL) {
dependencies = dep;
curr_dep = dep;
} else {
curr_dep->next_dep = dep;
curr_dep = dep;
}
}
} else {
// Parse the action
Action *act = malloc(sizeof(Action));
char **args = malloc(sizeof(char **));
strcpy(args[0], target);
int i = 1;
while (token != NULL) {
strcpy(args[i],token);
token = strtok(NULL, " \t\n");
i++;
}
args[i] = NULL;
act->args = args;
if (actions == NULL) {
actions = act;
curr_act = act;
} else {
curr_act->next_act = act;
curr_act = act;
}
}
// Create a new Rule node.
Rule *rule = malloc(sizeof(Rule));
strcpy(rule->target, target);
rule->dependencies = dependencies;
rule->actions = actions;
if (head_rule == NULL) {
head_rule = rule;
curr_rule = rule;
} else {
curr_rule->next_rule = rule;
curr_rule = rule;
}
}
return head_rule;
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T18:24:31.372Z | General Question | v2 | Use stat to get the last modified time (mtime) of a file. give example on how to call stat | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T18:27:29.850Z | General Question | v2 | the field of the stat struct that you want is called st_mtim on Linux. It has different names on Mac OSX. what is it? | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T18:29:34.491Z | General Question | v2 | what is execvp? How does it work? | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T18:45:23.393Z | Help Write Code | v2 | null | null | null | implement function run_make: run_make takes a target as its first argument. It finds the rule in the rules data structure corresponding to the target, and evaluates it. If target is NULL, then run_make will evaluate the first target in the rules list.
Update each of the dependencies. In other words, recursively evaluate each dependency rule. |
63c648ea5f004bf4898d00e9 | 2023-03-15T21:28:32.600Z | Help Fix Code | v2 | for a space-seperated string, divide it by spaced and save each to a char array which is in an array. | Action *curr_act = curr_rule->actions;
while (fgets(line, MAXLINE, fp) && line[0] == '\t') {
Action *act = malloc(sizeof(Action));
char **args = NULL;
int count = 0;
while ((token = strtok(line, " \t\n")) != NULL) {
strcpy(args[count],token);
count++;
}
act->args = malloc((count + 1) * sizeof(char *));
for (int i = 0; i < count; i++) {
args[i] = malloc(strlen(token) + 1);
strcpy(act->args[i], args[i]);
}
act->args[count] = NULL; // Add a NULL point to the end of the array.
// Link actions to rule
if (curr_rule->actions == NULL) {
curr_rule->actions = act;
curr_act = act;
} else {
curr_act->next_act = act;
curr_act = act;
}
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T21:33:31.382Z | Help Fix Code | v2 | for a space-seperated string, divide it by spaced and save each to a char array which is in an array. | Action *curr_act = curr_rule->actions;
while (fgets(line, MAXLINE, fp) && line[0] == '\t') {
Action *act = malloc(sizeof(Action));
char **args = NULL;
int count = 0;
while ((token = strtok(line, " \t\n")) != NULL) {
args[count] = malloc(sizeof(char) * (strlen(token) + 1));
strcpy(args[count],token);
args[count][strlen(token)] = '\0';
count++;
}
act->args = malloc((count + 1) * sizeof(char *));
for (int i = 0; i < count; i++) {
strcpy(act->args[i], args[i]);
}
act->args[count] = NULL; // Add a NULL point to the end of the array.
// Link actions to rule
if (curr_rule->actions == NULL) {
curr_rule->actions = act;
curr_act = act;
} else {
curr_act->next_act = act;
curr_act = act;
}
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T23:12:11.276Z | Help Fix Code | v2 | Check if the rule already exits. | Dependency *curr_dep = curr_rule->dependencies;
token = strtok(NULL, " :\t\n");
while (token != NULL) {
Dependency *dep = malloc(sizeof(Dependency));
// Check if the rule already exits.
Rule *dep_rule = head_rule;
while (dep_rule != NULL) {
if (strcmp(dep_rule->target, token) == 0) { // If exits, link that rule to the dependency.
dep->rule = dep_rule;
break;
}
dep_rule = dep_rule->next_rule;
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T23:13:11.573Z | Question from Code | v2 | what error on the step "strcmp(dep_rule->target, token)"? | Dependency *curr_dep = curr_rule->dependencies;
token = strtok(NULL, " :\t\n");
while (token != NULL) {
Dependency *dep = malloc(sizeof(Dependency));
Rule *dep_rule = head_rule;
while (dep_rule != NULL) {
if (strcmp(dep_rule->target, token) == 0) {
dep->rule = dep_rule;
break;
}
dep_rule = dep_rule->next_rule;
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-03-15T23:14:34.528Z | Question from Code | v2 | Do I need to free "rule"? | Rule *curr_rule = head_rule;
if (head_rule == NULL) {
Rule *rule = malloc(sizeof(Rule));
head_rule = rule;
curr_rule = rule;
} else {
while (curr_rule->next_rule != NULL) {
if (strcmp(curr_rule->target, token) == 0) {
break;
}
curr_rule = curr_rule->next_rule;
}
if (strcmp(curr_rule->target, token) != 0) {
Rule *rule = malloc(sizeof(Rule));
curr_rule->next_rule = rule;
curr_rule = curr_rule->next_rule;
}
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-05T19:07:44.713Z | Explain Code | v2 | null | struct sockaddr_in *self = init_server_addr(PORT);
int listenfd = set_up_server_socket(self, 5);
while (1) {
int fd = accept_connection(listenfd);
if (fd < 0) {
continue;
}
char buf[BUFSIZE];
int nbytes;
while ((nbytes = read(fd, buf, sizeof(buf) - 1)) > 0) {
buf[nbytes] = '\0';
printf("Next message: %s\n", buf);
}
close(fd);
}
free(self);
close(listenfd);
return 0; | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-05T19:09:46.274Z | General Question | v2 | how to get the length of a string | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-05T19:29:38.579Z | Explain Code | v2 | null | struct sockaddr_in *self = init_server_addr(PORT);
int listenfd = set_up_server_socket(self, 5);
while (1) {
int fd = accept_connection(listenfd);
if (fd < 0) {
continue;
}
char buf[BUFSIZE];
int nbytes;
while ((nbytes = read(fd, buf, sizeof(buf) - 1)) > 0) {
buf[nbytes] = '\0';
printf("Next message: %s\n", buf);
}
close(fd);
}
free(self);
close(listenfd);
return 0; | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-05T19:30:07.746Z | General Question | v2 | what does memmove do? | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-06T00:43:48.057Z | Help Write Code | v2 | null | null | null | create two new files: a friend_server.c file (with a stubbed main function) and a Makefile that compiles a program called friend_server. It must use the gcc flags -g, -std=gnu99, -Wall, and -Werror. In addition to building your code, your Makefile must permit choosing a port at compile-time. To do this, first add a #define to your program to define the port number on which the server will expect connections (this is the port based on your student number): |
63c648ea5f004bf4898d00e9 | 2023-04-06T01:28:56.865Z | Explain Code | v2 | null | char* users_str = NULL;
int len = 0;
struct user_node* curr = head;
while (curr != NULL) {
len += snprintf(NULL, 0, "%s\n", curr->user);
curr = curr->next;
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-06T05:08:50.135Z | Explain Code | v2 | null | int on = 1;
int status = setsockopt([sock_fd], SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on));
if (status == -1) {
perror("setsockopt -- REUSEADDR");
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-25T20:50:22.427Z | Question from Code | v2 | why do we use while(1)? | int fd[2];
int write_val = 1;
void send_one(int signal) {
write(fd[1], &write_val, sizeof(int));
}
int main() {
pipe(fd);
int pid = fork();
if (pid == 0) {
close(fd[0]);
struct sigaction sa;
sa.sa_handler = send_one;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
sigaction(SIGUSR1, &sa, NULL);
while (1)
;
} else if (pid > 0) {
close(fd[1]);
int count = 0;
while (1) {
int num = 0;
int num_read = read(fd[0], &num, sizeof(int));
if (num_read == sizeof(int) && num == 1) {
count++;
printf("%d\n", count);
}
}
}
return 0;
} | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-25T21:29:36.400Z | General Question | v2 | Write a shell script that adds every subdirectory of your current working directory to your PATH variable. Note
that the PATH variable requires an absolute path to each subdirectory. Remember that the environment variable PWD
stores the absolute path to the current working directory. (Do not recurse into subdirectories.) | null | null | null |
63c648ea5f004bf4898d00e9 | 2023-04-25T22:00:08.257Z | General Question | v2 | how to use execl? Give me examples | null | null | null |
63c648ee5f004bf4898d0111 | 2023-01-17T18:53:22.604Z | General Question | v1 | What is a pointer | null | null | null |
63c648f15f004bf4898d0125 | 2023-01-30T21:40:02.512Z | Help Fix Code | v1 | null | char permission[9];
int size;
int num_larger = 0;
scanf("%*s%*d");
while ((scanf("%s%*d%*s%*s%d%*s%*d%*s%*s", permission, &size) != EOF)){
if ((int)strtol(argv[1], NULL, 10) < size){
printf("%d%d", (int)strtol(argv[1], NULL, 10), size);
if (argc == 3){
printf(" op1 -%d ", num_larger);
num_larger += check_permissions(argv[2], permission);
}
else{
printf(" op2 -%d ", num_larger);
num_larger += 1;
}
}
} | Increase num_larger when the standard input argv[1] is greater than size | null |
63c648f15f004bf4898d0125 | 2023-01-30T21:42:16.783Z | Help Fix Code | v1 | null | int num = (int)strtol(*argv[1], NULL, 10); | Convert argv[1] to an int. | null |
63c648f15f004bf4898d0125 | 2023-02-10T20:39:49.246Z | Help Fix Code | v1 | null | struct pixel **read_pixel_array(FILE *image, int pixel_array_offset, int width, int height) {
struct pixel **pixel_data = malloc(sizeof(struct pixel) * height);
fseek(image, 10, pixel_array_offset);
for (int i = 0; i < height; i ++){
pixel_data[i] = malloc(sizeof(struct pixel) * width);
}
for (int i = 0; i < height; i ++){
for (int j = 0; j < width; j ++){
struct pixel temp;
fread(&temp.blue, 1, 1, image);
fread(&temp.green, 1, 1, image);
fread(&temp.red, 1, 1, image);
pixel_data[i][j] = temp;
}
}
return pixel_data;
} | Read and store bitmap pixel array. | null |
63c648f15f004bf4898d0125 | 2023-02-10T21:01:07.328Z | Help Fix Code | v1 | null | FILE *image = fopen(argv[1], "rb");
int pixel_array_offset, width, height;
read_bitmap_metadata(image, &pixel_array_offset, &width, &height);
// Print out metadata.
printf("Pixel array offset: %d\n", pixel_array_offset);
printf("Width: %d\n", width);
printf("Height: %d\n", height);
// Read in the pixel data
struct pixel **pixels = read_pixel_array(image, pixel_array_offset, width, height);
fclose(image);
for (int i = 0; i < height; i ++){
free(pixels[i]);
} | free image and pixels | null |
63c648f15f004bf4898d0125 | 2023-02-10T21:09:48.717Z | Help Fix Code | v1 | null | void read_bitmap_metadata(FILE *image, int *pixel_array_offset, int *width, int *height) {
fread(pixel_array_offset, 10, 4, image);
fseek(image, 18, *pixel_array_offset);
fread(width, 4, 1, image);
fseek(image, 22, *pixel_array_offset);
fread(height, 4, 1, image);
}
| Update pointers to pixel_array_offsey, width, and height for a bitmap | null |
63c648f15f004bf4898d0125 | 2023-02-15T14:58:21.565Z | Help Fix Code | v1 | null | int create_user(const char *name, User **user_ptr_add) {
// Check if name is too long
if (strlen(name) >= MAX_NAME){
}
User *new_user = (User*) malloc(sizeof(User));
strncpy(new_user->name, name, MAX_NAME);
for (int i = 0; i < MAX_FRIENDS; i ++){
new_user->friends[i] = NULL;
}
new_user->first_post = NULL;
new_user->next = NULL;
// If user_ptr_add is empty, add the new user.
if (*user_ptr_add == NULL){
// *user_ptr_add = (User*) malloc(sizeof(User));
*user_ptr_add = new_user;
return 0;
}
// If not empty, traverse the list.
User *curr = *user_ptr_add;
while (curr->next != NULL){
if (curr->name == name){
return 1;
}
curr = curr->next;
}
curr->next = (User*) malloc(sizeof(User*));
(curr->next) = new_user;
return 0;
} | Insert a User into the end of the linked list *user_ptr_add | null |
63c648f15f004bf4898d0125 | 2023-02-15T15:01:22.567Z | Help Fix Code | v1 | null | User *new_user = (User*) malloc(sizeof(User));
// If user_ptr_add is empty, add the new user.
if (*user_ptr_add == NULL){
*user_ptr_add = new_user;
return 0;
}
| *user_ptr_add is an empty linked list. Make it point to new_user; | null |
63c648f15f004bf4898d0125 | 2023-02-15T22:11:34.197Z | Help Fix Code | v1 | null | if (curr1 == NULL){
curr1 = user2;
printf("%s", ((*(curr1->friends)[0]).name));
}
else{
while (curr1 != NULL){
if (curr1->next == NULL){
break;
}
curr1 = curr1->next;
}
curr1->next = user2;
}
| trying to insert user2 at tail of linked list pointed to by curr1 | null |
63c648f15f004bf4898d0125 | 2023-02-15T22:51:56.195Z | Help Fix Code | v1 | null | /* Creates and returns pointer to new User with given name and next value. */
User *create_new_user(const char* name, User *next) {
User *new_user = calloc(1, sizeof(User));
strncpy(new_user->name, name, MAX_NAME);
*(new_user->friends) = calloc(MAX_FRIENDS, sizeof(User));
for (int i = 0; i < MAX_FRIENDS; i ++){
(new_user->friends)[i] = calloc(1, sizeof(User));
(new_user->friends)[i] = NULL;
}
new_user->first_post = NULL;
(new_user->profile_pic)[0] = '\0';
new_user->next = next;
return new_user;
}
| Creates a new dynamically allocated User with dynamically allocated friends attribute | null |
63c648f15f004bf4898d0125 | 2023-02-16T00:30:27.403Z | Help Fix Code | v1 | null | int make_friends(const char *name1, const char *name2, User *head) {
User *user1;
User *user2;
// Check if name1 is in list
user1 = find_user(name1, head);
if (!user1){
return 4;
}
// Check if name2 is in list
user2 = find_user(name2, head);
if (!user2){
return 4;
}
//Check if the same user is passed in twice.
if (name1 == name2){
return 3;
}
// Then, name1 and name2 are in the list, check if users have max friend size.
int len1 = list_length(user1->friends);
int len2 = list_length(user2->friends);
if (len1 >= MAX_FRIENDS || len2 >= MAX_FRIENDS){
return 2;
}
// Then, check if name1 and name2 are already friends.
for (int i = 0; i < MAX_FRIENDS; i++){
if ((user1->friends)[i] != NULL && strcmp((user1->friends)[i]->name, name2)){
return 1;
}
}
// Then, all conditions are met. Add the new friends to both lists.
for (int i = 0; i < MAX_FRIENDS; i++){
if (user1->friends[i] == NULL){
user1->friends[i] = user2;
break;
}
}
for (int i = 0; i < MAX_FRIENDS; i++){
if (user2->friends[i] == NULL){
user2->friends[i] = user1;
break;
}
}
return 0;
} | Add user1 to user2's friends array and user 2 to user 1's friends array. | null |
63c648f15f004bf4898d0125 | 2023-02-16T01:14:59.936Z | Help Fix Code | v1 | null | User *find_user(const char *name, const User *head) {
User *curr = (User*)head;
while (curr!= NULL){
if (strcmp(curr->name, name) == 0){
return (User *) curr;
}
curr = curr->next;
}
return NULL;
} | Find and return the user with name in the linked list starting at head | null |
63c648f15f004bf4898d0125 | 2023-03-15T03:09:24.589Z | Help Fix Code | v2 | replace all '\n' in curr_line with '\0' | char curr_line[MAXLINE];
for (int i = 0; i < MAXLINE; i ++){
if (curr_line[i] == '\n'){
curr_line[i] = '\0';
}
} | null | null |
63c648f15f004bf4898d0125 | 2023-03-15T13:49:24.809Z | Help Fix Code | v2 | Create a new rule and add it to the linked list pointed to by curr_rule | Rule *new_rule;
new_rule = create_rule_dependencies(curr_line, first_rule, curr_rule);
//printf("%s", new_rule->target);
// Check if this is the first rule being parsed
if (first_rule == NULL){
first_rule = new_rule;
}
else{
curr_rule->next_rule = new_rule;
//printf("%s", curr_rule->target);
}
curr_rule = new_rule;
printf("%s", curr_rule->target); | null | null |
63c648f15f004bf4898d0125 | 2023-03-15T13:50:06.556Z | Help Fix Code | v2 | Create a new rule and add it to the linked list pointed to by curr_rule
| Rule *new_rule;
new_rule = create_rule_dependencies(curr_line, first_rule, curr_rule);
//printf("%s", new_rule->target);
// Check if this is the first rule being parsed
if (first_rule == NULL){
first_rule = new_rule;
}
else{
curr_rule->next_rule = new_rule;
//printf("%s", curr_rule->target);
}
curr_rule = new_rule; | null | null |
63c648f15f004bf4898d012a | 2023-02-14T21:48:14.664Z | Question from Code | v1 | segmentation fault, how do I make this run when user_ptpr_add is NULL | int create_user(const char *name, User **user_ptr_add) {
if (strlen(name) >= MAX_NAME){
// if name is too long
return 2;
}
User *current = *user_ptr_add;
while (current != NULL) {
if (strcmp(current->name, name) == 0) {
// If a user by this name already exists in this list
return 1;
}
current = current->next;
// current should traverse to the end of the linkedlist
}
// Create user
User *new_user = (User*) malloc(sizeof(User));
if (new_user == NULL) {
return -1; // failed to allocate memory
}
strcpy(new_user->name, name);
new_user->profile_pic[0] = '\0';
new_user->first_post = NULL;
memset(new_user->friends, 0, sizeof(new_user->friends));
new_user->next = NULL;
// Add to user_ptr_add == current
if (user_ptr_add == NULL){
*user_ptr_add = new_user;
} else {
User *tail = *user_ptr_add;
while (tail->next != NULL) {
tail = tail->next;
}
tail->next = new_user;
}
return 0;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-14T21:54:08.458Z | Question from Code | v1 | how to avoid a memory leak from this code | int create_user(const char *name, User **user_ptr_add) {
if (strlen(name) >= MAX_NAME){
// if name is too long
return 2;
}
User *current = *user_ptr_add;
while (current != NULL) {
if (strcmp(current->name, name) == 0) {
// If a user by this name already exists in this list
return 1;
}
current = current->next;
// current should traverse to the end of the linkedlist
}
// Create user
User *new_user = (User*) malloc(sizeof(User));
if (new_user == NULL) {
return -1; // failed to allocate memory
}
strcpy(new_user->name, name);
new_user->profile_pic[0] = '\0';
new_user->first_post = NULL;
memset(new_user->friends, 0, sizeof(new_user->friends));
new_user->next = NULL;
// Add to user_ptr_add == current
if (user_ptr_add == NULL){
*user_ptr_add = new_user;
} else {
User *tail = *user_ptr_add;
while (tail->next != NULL) {
tail = tail->next;
}
tail->next = new_user;
}
return 0;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-15T00:42:19.412Z | Question from Code | v1 | I get this error "error: passing 'const User *' (aka 'const struct user *') to parameter of type 'User *' (aka 'struct user *') discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
if (already_friends(author, target) == 1){" | int make_post(const User *author, User *target, char *contents) {
if ((author == NULL) || (target == NULL)){
// if either User pointer is NULL
return 2;
}
if (already_friends(author, target) == 1){
// if users exist but are not friends
return 1;
}
// Create Post
Post *new_post = (Post*) malloc(sizeof(Post));
if (strcpy(new_post->author, author->name) == NULL) {
free(new_post);
}
if (strcpy(new_post->contents, contents) == NULL) {
free(new_post);
}
time_t curtime;
time(&curtime);
new_post->date = &curtime;
// Insert the new post at the *front* of the user's list of posts.
if (target->first_post == NULL) {
// If target does not have any post
target->first_post = new_post;
return 0;
}
Post *tail = target->first_post;
while (tail->next != NULL) {
tail = tail->next;
}
tail->next = new_post;
return 0;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-15T01:18:13.347Z | Question from Code | v1 | error: result of comparison against a string literal is unspecified (use an explicit string comparison function instead) [-Werror,-Wstring-compare]
if (user->profile_pic[0] != "\0") { | int print_user(const User *user) {
if (!user) {
// if the user is NULL
return -1;
}
if (user->profile_pic[0] != "\0") {
// if user has profile picture, print picture
}
printf("Name: %s\n", user->name);
printf("------------------------------------------");
printf("Friends:\n");
int i = 0;
while (i < MAX_FRIENDS && user->friends[i]) {
printf("%s\n", user->friends[i]->name);
i++;
}
printf("------------------------------------------");
printf("Posts:\n");
Post *head = user->first_post;
while (head->next != NULL) {
printf("From: %s\n", user->first_post->author);
printf("Date: %s\n\n", ctime(user->first_post->date));
printf("%s\n\n", user->first_post->contents);
printf("===\n");
}
printf("------------------------------------------");
return 0;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-15T01:47:14.287Z | Question from Code | v1 | expression must be a modifiable lvalue
for new_user->friends = { NULL }; | int create_user(const char *name, User **user_ptr_add) {
if (strlen(name) >= MAX_NAME){
// if name is too long
return 2;
}
// Create User
User *new_user = (User*) malloc(sizeof(User));
if (new_user == NULL) {
free(new_user);
return -1; // failed to allocate memory
}
if (strcpy(new_user->name, name) == NULL) {
free(new_user);
}
new_user->profile_pic[0] = '\0';
new_user->first_post = NULL;
new_user->friends = { NULL };
new_user->next = NULL;
if (*user_ptr_add == NULL) {
// If 0 users exists in the system
*user_ptr_add = new_user;
return 0;
}
if (find_user(name, *user_ptr_add) != NULL) {
// If a user by this name already exists in this list
return 1;
}
User *tail = *user_ptr_add;
while (tail->next != NULL) {
tail = tail->next;
}
tail->next = new_user;
return 0;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-15T01:50:24.211Z | Question from Code | v1 | error: comparison of array 'user->friends' equal to a null pointer is always false [-Werror,-Wtautological-pointer-compare]
if (user->friends == NULL) { | int delete_user(const char *name, User **user_ptr_del) {
User *user = find_user(name, *user_ptr_del);
if (user == NULL){
// if a user with this name does not exist.
return 1;
}
if (user->friends == NULL) {
// user does not have any friends
User *current = *user_ptr_del;
User *prev = NULL;
while (current != NULL) {
if (strcmp(current->name, name) == 0) {
if (prev == NULL) {
// The user to delete is at the head of the list
*user_ptr_del = current->next;
} else {
prev->next = current->next;
}
free(current);
return 0;
}
prev = current;
current = current->next;
}
return 1;
}
// Remove the deleted user from any lists of friends.
for (int i = 0; i < MAX_FRIENDS; i++){
if (user->friends[i] != NULL){
int j = 0;
while (user->friends[i]->friends[j] != NULL) {
if (user->friends[i]->friends[j] == user) {
// Remove the current user from this friend's list
for (int k = j; k < MAX_FRIENDS - 1; k++) {
user->friends[i]->friends[k] = user->friends[i]->friends[k + 1];
}
user->friends[i]->friends[MAX_FRIENDS - 1] = NULL;
break;
}
j++;
}
}
}
// delete the user from the list pointed to by *user_ptr_del
User *current = *user_ptr_del;
User *prev = NULL;
while (current != NULL) {
if (strcmp(current->name, name) == 0) {
if (prev == NULL) {
// The user to delete is at the head of the list
*user_ptr_del = current->next;
} else {
prev->next = current->next;
}
free(current);
return 0;
}
prev = current;
current = current->next;
}
return 1;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-15T02:03:24.306Z | Question from Code | v1 | segmentation fault | int make_post(const User *author, User *target, char *contents) {
if ((author == NULL) || (target == NULL)){
// if either User pointer is NULL
return 2;
}
if (already_friends(author, target) == 1){
// if users exist but are not friends
return 1;
}
// Create Post
Post *new_post = (Post*) malloc(sizeof(Post));
if (strcpy(new_post->author, author->name) == NULL) {
free(new_post);
}
if (strcpy(new_post->contents, contents) == NULL) {
free(new_post);
}
time_t curtime;
time(&curtime);
new_post->date = &curtime;
// Insert the new post at the front of the user's list of posts.
if (target->first_post == NULL) {
// If target does not have any post
target->first_post = new_post;
return 0;
}
Post *tail = target->first_post;
while (tail->next != NULL) {
tail = tail->next;
}
tail->next = new_post;
return 0;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-15T02:32:23.860Z | Question from Code | v1 | Why doesn't my code print out the post information: from, date, contents | int print_user(const User *user) {
if (!user) {
// if the user is NULL
return -1;
}
if (strcmp(user->profile_pic, "\0") != 0){
// if user has profile picture, print picture
}
printf("Name: %s\n", user->name);
printf("------------------------------------------\n");
printf("Friends:\n");
int i = 0;
while (i < MAX_FRIENDS && user->friends[i]) {
printf("%s\n", user->friends[i]->name);
i++;
}
printf("------------------------------------------\n");
printf("Posts:\n");
if (user->first_post == NULL) {
// user has no posts
printf("------------------------------------------\n");
return 0;
}
Post *head = user->first_post;
while (head->next != NULL) {
printf("From: %s\n", user->first_post->author);
printf("Date: %s\n\n", ctime(user->first_post->date));
printf("%s\n\n", user->first_post->contents);
printf("===\n");
}
printf("------------------------------------------\n");
return 0;
}
| null | null |
63c648f15f004bf4898d012a | 2023-02-15T02:57:49.014Z | Question from Code | v1 | This function doesn't match the output for this "Name: david
------------------------------------------
Friends:
bogdan
michelle
------------------------------------------
Posts:
From: michelle
Date: Fri Jan 27 14:40:07 2023
Isn't 209 fun?
===
From: bogdan
Date: Fri Jan 27 14:40:07 2023
david is soooo cool :)
------------------------------------------" | int make_friends(const char *name1, const char *name2, User *head) {
User *user1 = find_user(name1, head);
User *user2 = find_user(name2, head);
if ((user1 == NULL) || (user2 == NULL)) {
// if at least one user does not exist.
return 4;
}
if (user1 == user2) {
// if the same user is passed in twice.
return 3;
}
if (is_full(user1) || is_full(user2)) {
// if the users are not already friends, but at least one already has
// MAX_FRIENDS friends.
return 2;
}
if (already_friends(user1, user2) == 0) {
// if the two users are already friends.
return 1;
}
int i = 0;
while (i < MAX_FRIENDS && user1->friends[i]) {
i++;
}
user1->friends[i] = user2;
i = 0;
while (i < MAX_FRIENDS && user2->friends[i]) {
i++;
}
user2->friends[i] = user1;
return 0;
}
/*
* Print a user profile.
* For an example of the required output format, see the example output
* linked from the handout.
* Return:
* - 0 on success.
* - 1 if the user is NULL.
*/
int print_user(const User *user) {
if (user == NULL) {
// if the user is NULL
return -1;
}
if (strcmp(user->profile_pic, "\0") != 0){
// if user has profile picture, print picture
}
printf("Name: %s\n", user->name);
printf("------------------------------------------\n");
// Print list of friends
printf("Friends:\n");
int i = 0;
while (i < MAX_FRIENDS && user->friends[i]) {
printf("%s\n", user->friends[i]->name);
i++;
}
printf("------------------------------------------\n");
// Print list of posts
printf("Posts:\n");
printf("------------------------------------------\n");
Post *current_post = user->first_post;
while (current_post != NULL) {
printf("From: %s\n", current_post->author);
printf("Date: %s", ctime(current_post->date));
printf("\n%s\n\n", current_post->contents);
printf("===", current_post->contents);
current_post = current_post->next;
}
return 0;
}
| null | null |
63c648f15f004bf4898d012a | 2023-02-15T03:31:04.156Z | Question from Code | v1 | Code prints out an extra character "�" when reading and printing from an ASCII file | int print_user(const User *user) {
if (user == NULL) {
// if the user is NULL
return -1;
}
if (strcmp(user->profile_pic, "\0") != 0){
char ch;
FILE* ptr;
ptr = fopen(user->profile_pic, "r");
do {
ch = fgetc(ptr);
printf("%c", ch);
// Checking if character is not EOF.
// If it is EOF stop reading.
} while (ch != EOF);
// Closing the file
fclose(ptr);
}
printf("\nName: %s\n", user->name);
printf("------------------------------------------\n");
// Print list of friends
printf("Friends:\n");
int i = 0;
while (i < MAX_FRIENDS && user->friends[i]) {
printf("%s\n", user->friends[i]->name);
i++;
}
printf("------------------------------------------\n");
// Print list of posts
printf("Posts:\n");
Post *current_post = user->first_post;
while (current_post != NULL) {
printf("From: %s\n", current_post->author);
printf("Date: %s", ctime(current_post->date));
printf("\n%s\n", current_post->contents);
if (current_post->next != NULL){
printf("\n===\n\n");
}
current_post = current_post->next;
}
printf("------------------------------------------\n");
return 0;
} | null | null |
63c648f15f004bf4898d012a | 2023-02-15T03:57:01.883Z | Question from Code | v1 | Why is the date printed "Fri May 1 14:13:20 2139" not correct? | int make_post(const User *author, User *target, char *contents) {
if ((author == NULL) || (target == NULL)){
// if either User pointer is NULL
return 2;
}
if (already_friends(author, target) == 1){
// if users exist but are not friends
return 1;
}
// Create Post
Post *new_post = (Post*) malloc(sizeof(Post));
if (new_post == NULL) {
// failed to allocate memory
return -1;
}
if (strcpy(new_post->author, author->name) == NULL) {
free(new_post);
}
new_post->contents = strdup(contents);
if (new_post->contents == NULL) {
free(new_post);
return -1;
}
time_t curtime;
time(&curtime);
new_post->date = &curtime;
// Insert the new post at the *front* of the user's list of posts.
new_post->next = target->first_post;
target->first_post = new_post;
return 0;
}
| null | null |