redef stack

#include<stdio.h>
#include<stdlib.h>
#define max 10

struct stack
{
    int count;
    int top;
    int items[max];
};

void main()
{
    int i,j,b=1,a,pp,n;
    struct stack p1;
    p1.top=-1;
    p1.count=1;
    printf("enter choice\n1 to push\n2 to pop\n3 to display\n");
    while(b!=0)
    {
    scanf("%d",&i);
    switch(i)
    {
    case 1:
        printf("enter the number of elements to push \n");
        scanf("%d",&n);
        printf("enter the element to push\n");
        for(j=1;j<=n;j++)
        {
        scanf("%d",&a);
        if(p1.top==max)
        {
            printf("stack is full\n only %d elements can be pushed\n",&j);

        }
        else
        {
            p1.top++;
            p1.items[p1.top]=a;
            p1.count++;
        }
        }
        break;

    case 2:

    if(p1.top==-1)
    {
        printf("stack is empty\n");

    }
    else
    {
        pp=p1.items[p1.top];
        p1.top--;
        p1.count--;
        printf("the popped element is %d\n",pp);
    }


        break;

    case 3:
        printf("the elements of a stack are:\n");
        for(j=1;j<(p1.count);j++)
            printf("%d\n",(p1.items[j-1]));
        break;

    default:
        printf("invalid operator\n");
        break;
    }
    printf("enter 1 to continue or 0 to exit\n");
    scanf("%d",&b);
    if(b==1)
        printf("enter choice\n");
    }
}