Stacks as an Array

Write a program for a stack as an Array.

#include<iostream.h>
using namespace std;
#define size 20

void push(int X[], int &t,int);
int pop(int X[], int &t);
void show(int X[], int t);

void main()
{
int ch, X[size],n;
int top=-1;
do
{
cout<<endl<<"Choose any of the following options:"<<endl;
cout<<"1.Push"<<endl;
cout<<"2.Pop"<<endl;
cout<<"3.Show"<<endl;
cout<<"4.Exit"<<endl;
cout<<"Enter the choice:"<<endl;
cin>>ch;
 switch(ch)
 {
  case 1: cout<<"Enter the number to insert:";
      cin>>n;
      push(X,top,n);
      break;
  case 2: cout<<pop(X,top);
      break;
  case 3:
      show(X,top);
      break;
 }
} while(ch!=4);
}

void push(int X[], int& t, int num)
{
 if(t==size-1)
    cout<<"Stack is overflow";
 else
   {
    t++;
    A[t]=num;
 }
}
int pop(int A[], int& t)
{
int a;
 if(t==-1)
   cout<<"Stack is underflow";
 else
   {
     a=X[t];
     t--;
   }
 return a;
}
void show(int X[], int t)
{
 if(t==-1)
   cout<<"Can't show";
 else
  {
    for(int i=t;i>=0;i--)
    cout<<X[i]<<" ";
  }
}

/*
Menu:
1.Push
2.Pop
3.Show
4.Exit
Enter the choice:
1
Enter the number to insert:
13

Menu:
1.Push
2.Pop
3.Show
4.Exit
Enter the choice:
1
Enter the number to insert:
41

Menu:
1.Push
2.Pop
3.Show
4.Exit
Enter the choice:
2
13

Menu:
1.Push
2.Pop
3.Show
4.Exit
Enter the choice:
3
41

Menu:
1.Push
2.Pop
3.Show
4.Exit
Enter the choice:
4
*/