Link-List implementn

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

struct stack
{
    int info;
    struct stack *next;
}w;

typedef struct stack *ptr;
ptr start=NULL;

ptr getnode()
{
    ptr f;
    f=(ptr)malloc(sizeof(w));
    if(f==NULL)
    {
        printf("node could not be allocated\n");
        exit(1);
    }
    return f;
}

void main()
{
    int a,d,s,i,count=0,y=1;
    ptr p,q;
    printf("1 to inserting an element in the begining\n");
    printf("2 to inserting an element at the end\n");
    printf("3 to inserting an element at specified position\n");
    printf("4 to delete an element from specified position\n");
    printf("5 to display elements in the link list\n");
    do
    {
    printf("enter a choice\n");
    scanf("%d",&a);
    switch(a)
    {
    case 1:
        printf("enter the data to store\n");
        scanf("%d",&s);
        p=getnode();
        p->info=s;
        p->next=start;
        start=p;
        count++;
        break;

    case 2:
        if(start==NULL)
        {
            printf("enter the data to store\n");
            scanf("%d",&s);
            p=getnode();
            p->info=s;
            p->next=start;
            start=p;
            count++;
        }
        else
        {
            q=start;
            while((q->next)!=NULL)
                q=q->next;
            printf("enter the data to store\n");
            scanf("%d",&s);
            p=getnode();
            p->info=s;
            q->next=p;
            p->next=NULL;
            count++;
        }
        break;

    case 3:
        if(start==NULL)
            printf("link list is empty enter first element\n");
        else
        {
        printf("enter the position to enter after\n");
        scanf("%d",&d);
        if(d>count)
        {
            printf("position doesnt exist\n");
            break;
        }
        }
        q=start;
        for(i=1;i<d;i++)
            q=q->next;
        printf("enter the data to store\n");
        scanf("%d",&s);
        p=getnode();
        p->info=s;
        p->next=q->next;
        q->next=p;
        count++;
        break;

    case 4:
        if(start==NULL)
        {
            printf("link list is empty\n");
            break;
        }
        printf("enter the position to delete from:\n");
        scanf("%d",&d);
        if(d>count)
        {
            printf("position doesnt exist\n");
            break;
        }
        if(d==1)
        {
            q=start;
            printf("the element being deleted is %d\n",q->info);
            start=q->next;
            free(q);
            count--;
            break;
        }
        else
        {
            q=start;
            p=start;
            for(i=1;i<d-1;i++)
                p=p->next;
            for(i=1;i<d;i++)
                q=q->next;
            printf("the element being deleted is %d\n",q->info);
            p->next=q->next;
            free(q);
            count--;
        }
        break;

    case 5:
        if(start==NULL)
        {
            printf("link list is empty\n");
            break;
        }
        else
        {
            printf("elements of link list are: \n");
            q=start;
            while(q!=NULL)
            {
                printf("%d  ",q->info);
                q=q->next;
            }
            printf("\n");
        }
        break;

    default :
        printf("invalid option\n");
        break;
    }
    printf("enter 0 to exit or 1 to continue\n");
    scanf("%d",&y);
    }while(y!=0);
}