Demonstrate the Stack Class

Here is a Java Program to Demonstrate the Stack class.

import java.util.*;
 
class StackDemo {
  static void showpush(Stack st, int a) {
    st.push(new Integer(a));
    System.out.println("push(" + a + ")");
    System.out.println("stack: " + st);
  }

  static void showpop(Stack st) {
    System.out.print("pop -> ");
    Integer a = (Integer) st.pop();
    System.out.println(a);
    System.out.println("stack: " + st);
  }

  public static void main(String args[]) {
    Stack st = new Stack();

    System.out.println("stack: " + st);
    showpush(st, 42);
    showpush(st, 66);
    showpush(st, 99);
    showpop(st);
    showpop(st);
    showpop(st);
    try {
      showpop(st);
    } catch (EmptyStackException e) {
      System.out.println("empty stack");
    }
  }
}

Output of Above Java Program
stack: Stack@19821f
push(42)
stack: Stack@19821f
push(66)
stack: Stack@19821f
push(99)
stack: Stack@19821f
pop -> 99
stack: Stack@19821f
pop -> 66
stack: Stack@19821f
pop -> 42
stack: Stack@19821f
pop -> Stack underflow.
0
stack: Stack@19821f