Language: C

#include<stdio.h>
#include<stdlib.h>

struct node{
  struct node *right;
  struct node *left;
  struct node *parent;
  int key;
};
typedef struct node * Node;
#define NIL NULL

Node root;

Node treeMinimum(Node x){
  while(x.left != NIL)
    {
      x = x.left;
    }
  return x;
}

Node treeSearch(Node u, int k){
  if(u == NIL || k == x.key)
    {
      return u;
    }

  if(k < u.key)
    {
      return treeSearch(u.left, k);
    }
  else
    {
      return treeSearch(u.right, k);
    }
}

Node treeSuccessor(Node x){
  Node y;

  if(x.right != NIL)
    {
      return treeMinimum(x.right);
    }
  y = x.p;

}

void treeDelete(Node z){
  Node y; // node to be deleted
  Node x; // child of y

  if(z.left == NIL || z.right == NIL) y = z;
  else y = treeSuccessor(z);

  if(y.left != NIL) x = y.left;
  else x = y.right;

  if(x != NIL) x.parent = y.parent;

  if(y.parent


}

void insert(int k){
  Node y = NIL;
  Node x = root;
  Node z;

  z = malloc(sizeof(struct node));
  z->key = k;
  z->left = NIL;
  z->right = NIL;




}

void inorder(Node u){
  if(u != NIL)
    {
      inorder(u.left);
      printf("%d ", u.key);
      inorder(u.right);
    }
}

void preorder(Node u){
  if(u != NIL)
    {
      printf("%d ", u.key);
      inorder(u.left);
      inorder(u.right);
    }
}


int main()
{
  int n, i, x;
  char com[20];
  scanf("%d", &n);
  
  for ( i = 0; i < n; i++ )
    {
      scanf("%s", com);
      if ( com[0] == 'f' ){
	scanf("%d", &x);
	Node t = treeSearch(root, x);
	if ( t != NIL ) printf("yes\n");
	else printf("no\n");
      } else if ( com[0] == 'i' ){
	scanf("%d", &x);
	insert(x);
      } else if ( com[0] == 'p' ){
	inorder(root);
	printf("\n");
	preorder(root);
	printf("\n");
      } else if ( com[0] == 'd' ){
	scanf("%d", &x);
	treeDelete(treeSearch(root, x));
      }
    }
  
  return 0;
}

Compiler output:
main.c: In function 'treeMinimum':
main.c:16:10: error: 'x' is a pointer; did you mean to use '->'?
   16 |   while(x.left != NIL)
      |          ^
      |          ->
main.c:18:12: error: 'x' is a pointer; did you mean to use '->'?
   18 |       x = x.left;
      |            ^
      |            ->
main.c: In function 'treeSearch':
main.c:24:23: error: 'x' undeclared (first use in this function)
   24 |   if(u == NIL || k == x.key)
      |                       ^
main.c:24:23: note: each undeclared identifier is reported only once for each function it appears in
main.c:29:11: error: 'u' is a pointer; did you mean to use '->'?
   29 |   if(k < u.key)
      |           ^
      |           ->
main.c:31:26: error: 'u' is a pointer; did you mean to use '->'?
   31 |       return treeSearch(u.left, k);
      |                          ^
      |                          ->
main.c:35:26: error: 'u' is a pointer; did you mean to use '->'?
   35 |       return treeSearch(u.right, k);
      |                          ^
      |                          ->
main.c: In function 'treeSuccessor':
main.c:42:7: error: 'x' is a pointer; did you mean to use '->'?
   42 |   if(x.right != NIL)
      |       ^
      |       ->
main.c:44:27: error: 'x' is a pointer; did you mean to use '->'?
   44 |       return treeMinimum(x.right);
      |                           ^
      |                           ->
main.c:46:8: error: 'x' is a pointer; did you mean to use '->'?
   46 |   y = x.p;
      |        ^
      |        ->
main.c: In function 'treeDelete':
main.c:54:7: error: 'z' is a pointer; did you mean to use '->'?
   54 |   if(z.left == NIL || z.right == NIL) y = z;
      |       ^
      |       ->
main.c:54:24: error: 'z' is a pointer; did you mean to use '->'?
   54 |   if(z.left == NIL || z.right == NIL) y = z;
      |                        ^
      |                        ->
main.c:57:7: error: 'y' is a pointer; did you mean to use '->'?
   57 |   if(y.left != NIL) x = y.left;
      |       ^
      |       ->
main.c:57:26: error: 'y' is a pointer; did you mean to use '->'?
   57 |   if(y.left != NIL) x = y.left;
      |                          ^
      |                          ->
main.c:58:13: error: 'y' is a pointer; did you mean to use '->'?
   58 |   else x = y.right;
      |             ^
      |             ->
main.c:60:17: error: 'x' is a pointer; did you mean to use '->'?
   60 |   if(x != NIL) x.parent = y.parent;
      |                 ^
      |                 ->
main.c:60:28: error: 'y' is a pointer; did you mean to use '->'?
   60 |   if(x != NIL) x.parent = y.parent;
      |                            ^
      |                            ->
main.c:62:7: error: 'y' is a pointer; did you mean to use '->'?
   62 |   if(y.parent
      |       ^
      |       ->
main.c:62:14: error: expected ')' before '}' token
   62 |   if(y.parent
      |     ~        ^
      |              )
......
   65 | }
      | ~             
main.c:65:1: error: expected expression before '}' token
   65 | }
      | ^
main.c: In function 'inorder':
main.c:85:16: error: 'u' is a pointer; did you mean to use '->'?
   85 |       inorder(u.left);
      |                ^
      |                ->
main.c:86:22: error: 'u' is a pointer; did you mean to use '->'?
   86 |       printf("%d ", u.key);
      |                      ^
      |                      ->
main.c:87:16: error: 'u' is a pointer; did you mean to use '->'?
   87 |       inorder(u.right);
      |                ^
      |                ->
main.c: In function 'preorder':
main.c:94:22: error: 'u' is a pointer; did you mean to use '->'?
   94 |       printf("%d ", u.key);
      |                      ^
      |                      ->
main.c:95:16: error: 'u' is a pointer; did you mean to use '->'?
   95 |       inorder(u.left);
      |                ^
      |                ->
main.c:96:16: error: 'u' is a pointer; did you mean to use '->'?
   96 |       inorder(u.right);
      |                ^
      |                ->