#include<iostream.h>
 
int *Stack, top=-1, maxSize;
 
void createStack();
void push ();
void pop();
void dispStack();
 
int main()
{
  int choice=0, elem;
  while(choice!=5)
    {
      cout<<"\n\n Enter a choice :"
      <<"\n 1. Create a new empty stack"
      <<"\n 2. Push an element into stack"
      <<"\n 3. Pop an element from stack"
      <<"\n 4. Display the stack"
      <<"\n 5. Exit.\n\n";
      cin>>choice;
      switch (choice)
	{
	case 1:
	  createStack();
	  break;
	case 2:
	  push();
	  break;
	case 3:
	  pop();
	  break;
	case 4:
	  dispStack();
	  break;
	case 5:
	  exit(0);
	  break;
	default:
	  cout<<"\n Invalid choice.";
	  break;
	}
    }
}
 
void createStack()
{
  cout<<"\n Enter maximum size for stack : ";
  cin>>maxSize;
  Stack = new int[maxSize];
}
 
void push()
{
  if (top>=(maxSize-1))
    {
      cout<<"\n Overflow! Element cannot be pushed.";
    }
  else
    {
      top++;
      cout<<"\n Enter element to be pushed into stack : ";
      cin>>Stack[top];
    }
}
 
void pop()
{
  if (top<0)
    {
      cout<<"\n Underflow! Stack is empty, so no element can be popped.";
    }
  else
    {
      cout<<"\n The element that was popped : "<<Stack[top--];
    }
}
 
void dispStack()
{
  if (top<0)
    {
      cout<<"\n Stack is empty, no elements to display.";
    }
  else
    {
      cout<<"\n The stack is : ";
      for (int i=top;i>=0;i--)
	{
	  cout<<"\n"<<Stack[i];
	}
    }
}