insert at last singly

#include<stdio.h>
 #include<stdlib.h>
 typedef struct node
 {
     int a;
     struct node *next;
 }node;

 node *head=NULL;

 void insert_at_last()
 {
     node *N=(node*)malloc(sizeof(node));
     scanf(" %d", &N->a);
     N->next=NULL;

     node *list;

     if(head==NULL)
     {
         head=N;
         return;
     }
     else
     {
         while(list->next!=NULL)
         {
             list=list->next;
         }
         list->next=N;
         list=N;
     }
 }

 void display()
 {
     node *list=head;
     while(list!=NULL)
     {
         printf("Data: %d\n", list->a);
         list=list->next;
     }
 }


 int main()
 {
     int i,n;
     scanf("%d", &n);

     for(i=0; i<n; i++)
     {
         insert_at_last();
     }
     display();
 }