l

public class StackDemo {
 private static final int capacity = 3;
 int arr[] = new int[capacity];
 int top = -1;

 public void push(int pushedElement) {
  if (top < capacity - 1) {
   top  ;
   arr[top] = pushedElement;
   System.out.println("Element "   pushedElement
       " is pushed to Stack !");
   printElements();
  } else {
   System.out.println("Stack Overflow !");
  }
 }

 public void pop() {
  if (top >= 0) {
   top--;
   System.out.println("Pop operation done !");
  } else {
   System.out.println("Stack Underflow !");
  }
 }

 public void printElements() {
  if (top >= 0) {
   System.out.println("Elements in stack :");
   for (int i = 0; i <= top; i  ) {
    System.out.println(arr[i]);
   }
  }
 }

 public static void main(String[] args) {
  StackDemo stackDemo = new StackDemo();

  stackDemo.pop();
  stackDemo.push(23);
  stackDemo.push(2);
  stackDemo.push(73);
  stackDemo.push(21);
  stackDemo.pop();
  stackDemo.pop();
  stackDemo.pop();
  stackDemo.pop();
 }

}