doubly linked lists initiallisation

Question

Hello so i'm something new to linked lists and data structrs generally so i want to creat two functions one initiallise the doubly linked list and the other one print it but when i compile it it doesnt print anything where did i miss exactly (i heard that i should use the debugger but i didnt understand how to use it on Dev c++ IDE)

  #include <iostream>
#include <stdlib.h>
using namespace std;
struct Node
{   int data;
    Node *next;
    Node *previous;
};
Node *head,*end;


Node* insertion()
{   
    Node *first_node =new Node;
    if (head==NULL || first_node==NULL)
        exit(EXIT_FAILURE);
        
    first_node->data=10;
    first_node->previous=NULL;
    first_node->next=NULL;
    head=first_node;
    end=first_node;
    return head;
}
void affiche()
{
    Node *current;
    current=head;
    if(head==NULL)
     exit(EXIT_FAILURE);
    while(current->next!=NULL)
    {
        cout<<current->data <<" ";
        current=current->next;
    }
}
int main()
{

    Node *MyList=insertion();
    affiche();
    return 0;
}

Answer 1

Just change

while(current->next!=NULL)

to

while(current!=NULL)

Your version stops printing the list too early.

(But please learn how to use a debugger, you would have found this error very quickly with a debugger).

EDIT

You also need to remove this

if (head==NULL || first_node==NULL)
    exit(EXIT_FAILURE);

head==NULL is initially true and first_node==NULL is never true. (new never returns NULL). Since head==NULL is initially true your program is always going to quit at the point.

EDIT(2)

And remove this

if(head==NULL)
   exit(EXIT_FAILURE);

Why do you think printing an empty list is an error that means you have to exit the program? It's perfectly OK to print an empty list.