Doubly_max

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

typedef struct node
{

    int a;
    struct node*next;
    struct node*previous;
} node;
node*head;

void display()
{

    node*list=head;


    int k=list->a;

    while(list!=NULL)
    {

        if(k<list->a)
        {
            k=list->a;
        }

        list=list->next;
    }
     printf("\nMAX VALUE IS : %d\n",k);
}

void insert_at_end(int aN)
{

    node*N=(node*)malloc(sizeof(node));
    N->a=aN;
    N->next=NULL;
    N->previous=NULL;
    node*list=head;
    if(head==NULL)
    {
        head=N;
    }
    else
    {
        while(list->next!=NULL)
        {
            list=list->next;
            N->previous=list;
        }
        list->next=N;
        N->next=NULL;
        N->previous=list;


    }

}

int main()
{
    int i,x,af,l;
    head=NULL;
    printf("ENTER TOTAL INPUT :");
    scanf("%d",&l);
    for(i=0; i<l; i++)
    {
        scanf("%d",&af);
        insert_at_end(af);
    }


    display();



}