Stack.java

package com.basic.datastructure;

import java.util.ArrayList;

public class Stack {
	private ArrayList elementData = new ArrayList();

	public void push(Object o) {
		elementData.add(o);
	}

	public Object pop() {
		Object o=elementData.get(elementData.size()-1);
		elementData.remove(elementData.size()-1);
		return o;
	}

	public Object peek() {
		return elementData.get(elementData.size()-1);
	}

	public boolean isEmpty() {
		return elementData.isEmpty();
	}

	public int size() {
		return elementData.size();
	}
}