import java.util.Scanner;

interface StackADT

{

void push() throws Exception;

void pop();

void display();

}

class StackInterface implements StackADT

{

int size,top;

int arr[];

Scanner s = new Scanner(System.in);

StackInterface()

{

System.out.println("Enter the size of the stack");

size = s.nextInt();

arr = new int[size];

top = -1;

}

public void push() throws Exception

{

if(top == arr.length-1)

{

System.out.println("StackOverflow");

}

else

{

System.out.println("Enter the element to push in the stack");

int element = s.nextInt();

top = top+1;

arr[top] = element;

}

}

public void pop()

{

if(top == -1)

{

System.out.println("Stack Underflow");

}

else

{

System.out.println("The Popped element is "+ arr[top]);

top--;

}

}

public void display()

{

if(top == -1)

{

System.out.println("The Stack is empty");

}

else

{

for (int i=0;i<arr.length;i++)

{

System.out.println(arr[i]);

}

}

}

public static void main(String [] args) throws Exception

{

Scanner s = new Scanner(System.in);

System.out.println("Stack Array ADT");

StackInterface si = new StackInterface();

String ch ="y";

while(ch.equals("y"))

{

System.out.println("Stack Array operations");

System.out.println("1.Push\t2.Pop\t3.Display\t4.Exit");

System.out.println("Enter your choice");

int opt = s.nextInt();

switch(opt)

{

case 1: si.push(); break;

case 2: si.pop(); break;

case 3: si.display(); break;

case 4: System.exit(0);

default : System.out.println("Invalid option");

}

System.out.println("Do you want to continue (y/n)");

ch = s.next();

}

}

}