Stack

#include <stdio.h>
#define max 10
int a[100],n,f=0,x=0;
void cre()
{
    if(x==0)
    {
        int j;
        printf("\nEnter the value of Stack:\n");
        scanf("%d",&n);
        for(j=1;j<=n;j++)
        {
            a[j]==0;
        }
        x=1;
    }
    else
    {
       if(f==n)
       {
           printf("Stack is FULL:\n");
       }
       else
       {
        int i;
        printf("\nEnter the Stack data:\n");
        scanf("%d",&i);
        f++;
        a[f]=i;
       }
    }
}
void del()
{
    if(f==0) printf("\nStack is Empty.\n");
    else
    {
    printf("\nDeleted data is %d",a[f]);
    a[f]=0;
    f--;
    }
}
void dis()
{
    int i;
    for(i=n;i>=1;i--)
    {
        printf("%d ",a[i]);
    }

}

int main()
{
    int x;
    while(1)
    {
        printf("\n1:Ins,2:Del,3: Dis:\n");
    scanf("%d",&x);
    switch(x)
    {
    case 1:
        {
            cre();
            break;
        }
    case 2:
        {
            del();
            break;
        }
    case 3:
        {
            dis();
            break;
        }
    }
    }
}