PROGRAM FOR STACK DS IN C++

//program for stack
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
int top=-1;
struct stack
{
  char a[10];
}sat;
void push(stack s,char a)
{
  top++;
  s.a[top]=a;
}

char pop(stack s)
{
  char c=s.a[top];
  top--;
  return c;
}
int isempty(stack s)
{
  if(top==-1)
  return 1;
  else
  return 0;
}
int isfull(stack s)
{
  if(top==9)
  return 1;
  else
  return 0;
}
void main()
{
  char b[5];
  int i;
  clrscr();
  cout<<"enter the input:";
  gets(b);
  for(i=0;b[i]!='\0';i++)
  {
    push(sat,b[i]);
    pop(sat);
  }
  if(isempty(sat))
  cout<<"stack is empty";
  else
  cout<<"stack is not empty";
  getch();
}