Language: C++

#include<cstdio>
#include<cstdlib>
#include<cstring>
struct Node
{
    int key;
    Node *prev;
};
Node *nil;
Node* listSearch(int key)
{
    Node *cur=nil->next;
    while(cur!=nil&&cur->key!=key)
    {
        cur=cur->next;
    }
    return cur;
}
void init()
{
    nil=(Node*)malloc(sizeof(Node));
    nil->next=nil;
    nil->prev=nil;
}
void printList()
{
    Node *cur=nil->next;
    int isf=0;
    while(1) *next,
    {
        if(cur==nil) break;
        if(sif++>0) printf(" ");
        printf("%d",cur->key);
        cur=cur->next;
    }
    printf("\n");
}
void deleteNode(Node *t)
{
    if(t==nil) return;
    t->prev->next=t->next;
    t->next->prev=t->prev;
    free(t);
}
void deleteFirst()
{
    deleteNode(nil->next);
}
void deleteLast()
{
    deleteNode(nil->prev);
}
void deletekey(int key)
{
    deleteNode(listSearch(key));
}
void insert(int key)
{
    Node *x=(Node *)malloc(sizeof(Node));
    x->key=key;
    x->next=nil->next;
    nil->next->prev=x;
    nil->next=x;
    x->prev=nil;
}
int main()
{
    int key,n,i;
    int size=0;
    char com[20];
    int np=0,nd=0;
    scanf("%d",&n);
    init();
    for(i=0;i<n;i++)
    {
        scanf("%s%d",com,&key);
        if(com[0]=='i'){insert(key);np++;size++;}
        else if(com[0]=='d')
        {
            if(strlen(com)>6)
            {
                if(com[6]=='F') deleteFirst();
                else if(com[6]=='L') deleteLast();
            }
            else
            {
                deletekey(key);nd++;
            }
            size--;
        }
    }
    printList();
    return 0;
}

Compiler output:
a.cc: In function 'Node* listSearch(int)':
a.cc:12:20: error: 'struct Node' has no member named 'next'
   12 |     Node *cur=nil->next;
      |                    ^~~~
a.cc:15:18: error: 'struct Node' has no member named 'next'
   15 |         cur=cur->next;
      |                  ^~~~
a.cc: In function 'void init()':
a.cc:22:10: error: 'struct Node' has no member named 'next'
   22 |     nil->next=nil;
      |          ^~~~
a.cc: In function 'void printList()':
a.cc:27:20: error: 'struct Node' has no member named 'next'
   27 |     Node *cur=nil->next;
      |                    ^~~~
a.cc:29:15: error: 'next' was not declared in this scope
   29 |     while(1) *next,
      |               ^~~~
a.cc:30:5: error: expected primary-expression before '{' token
   30 |     {
      |     ^
a.cc: In function 'void deleteNode(Node*)':
a.cc:41:14: error: 'struct Node' has no member named 'next'
   41 |     t->prev->next=t->next;
      |              ^~~~
a.cc:41:22: error: 'struct Node' has no member named 'next'
   41 |     t->prev->next=t->next;
      |                      ^~~~
a.cc:42:8: error: 'struct Node' has no member named 'next'
   42 |     t->next->prev=t->prev;
      |        ^~~~
a.cc: In function 'void deleteFirst()':
a.cc:47:21: error: 'struct Node' has no member named 'next'
   47 |     deleteNode(nil->next);
      |                     ^~~~
a.cc: In function 'void insert(int)':
a.cc:61:8: error: 'struct Node' has no member named 'next'
   61 |     x->next=nil->next;
      |        ^~~~
a.cc:61:18: error: 'struct Node' has no member named 'next'
   61 |     x->next=nil->next;
      |                  ^~~~
a.cc:62:10: error: 'struct Node' has no member named 'next'
   62 |     nil->next->prev=x;
      |          ^~~~
a.cc:63:10: error: 'struct Node' has no member named 'next'
   63 |     nil->next=x;
      |          ^~~~