15.Doubly linked list (DS)

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
typedef struct node
{
    int data;
    struct node *next,*prev;
}node;
typedef struct
{
     node *start,*last;
}head;
void insertend(head *t,int ele)
{
    node *p;
    p = (node*)malloc(sizeof(node));
    p->data=ele;
    p->next=p->prev=NULL;
    if(t->start==NULL)
    {
        t->last=t->start=p;
        return;
    }
    t->last->next = p;
    p->prev = t->last;
    t->last = p;
    return ;
}
void displayrev(head *t)
{
    node *q;
    if(t->start==NULL&&t->last==NULL)
    {
        printf("\nLinked list is empty");
        return;
    }
    printf("\nElement of Linked list is given below\n");
    for(q=t->last;q!=NULL;q=q->prev)
    {
        printf("%d\t",q->data);
    }
    return;
}
void deletebeg(head *t)
{
    int z;
    node *p;
    if(t->start==NULL)
    {
        printf("Linked list is Empty");
        return;
    }
    p=t->start;
    z = p->data;
    if(t->start==t->last)
    {
        t->start=t->last=NULL;
    }
    else
    {
        t->start = t->start->next;
        t->start->prev = NULL;
    }
    printf("deleted element in Linked list %d",z);
    return;
}
void display(head *t)
{
    node *q;
    if(t->start==NULL&&t->last==NULL)
    {
        printf("\nLinked list is empty");
        return;
    }
    printf("\nElement of Linked list is given below\n");
    for(q=t->start;q!=NULL;q=q->next)
    {
        printf("%d\t",q->data);
    }
    return;
}
int main()
{
    head x;
    int ch,ele;
    x.start=x.last=NULL;
    printf("\nImplementation of Doubly Linked list with function insertend,display,deletebeg,reversedisplay\n");
    while(1)
    {
        printf("\nenter choice \n1.InsertEnd 2.Deletebeg 3.Reversedisplay 4.display 5.Exit\n");
        scanf_s("%d",&ch);
        if(ch==5)
        {
            break;
        }
        else
        {
            switch(ch)
            {
            case 1:printf("\nenter element to insert");
                scanf_s("%d",&ele);
                insertend(&x,ele);
                break;
            case 2:deletebeg(&x);
                break;
            case 3:displayrev(&x);
                break;
            case 4:display(&x);
                break;
            default:printf("\ninvalid input");
            }
        }
    }
    _getch();
    return 0;
}