stack using array

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


void push();
void pop();
void display();

int a[10],max,i;
int top=-1;


void push()
{int item;
if(top==max-1)
{
    printf("the stack is full\n");
}
else{
    printf("enter item to be pushed\n");
    scanf("%d",&item);
    top=top+1;
    a[top]=item;
}
}



void pop(){
if(top==-1){
    printf("Stack is empty\n");
}
else{
    printf("%d is poppped \n",a[top]);
    top=top-1;
}
}

void display(){
if(top==-1){
    printf("stack is empty\n");
}
else{
        for(i=0;i<=top;i++)
        {
            printf("%d\t",a[i]);
        }
        printf("\n");
}
}

void main()
{
    int ch;
    printf("nter max size : ");
    scanf("%d",&max);
    while(1)
    {
    printf("nter choice: \n 1 push \n 2 pop \n 3 disp \n");
    scanf("%d",&ch);
    switch(ch){
    case 1:push();
    break;
    case 2:pop();
    break;
    case 3:display();
    break;
    case 4:exit(0);
    default: printf("incvald ch\n");
    break;
    }
    }


}