package com.array.realize;

import java.util.Arrays;

class Mystack1<T> {

    private Object[] stack;

    private int size;
 
    Mystack1() {
        stack = new Object[20];
    }
 
 
    public boolean isEmpty() {
        return size == 0;
    }
 
 
    public T peek() {
        T t = null;
        if (size > 0)
            t = (T) stack[size - 1];
        return t;
    }
    
    public void push(T t) {

        stack[size] = t;
        size++;
    }
 

    public T pop() {
        T t = peek();
        if (size > 0) {
            stack[size - 1] = null;
            size--;
        }
        return t;
    }
 

}





public class ArrayStack {

	
	public static void main(String[] args) {
		 Mystack1<String> stack = new Mystack1<String>();
	        System.out.println(stack.peek());
	        System.out.println(stack.isEmpty());
	        stack.push("1");
	        stack.push("2");
	        stack.push("3");
	        System.out.println(stack.pop());
	        System.out.println(stack.isEmpty());
	        System.out.println(stack.peek());

		// TODO Auto-generated method stub

	}

}