用数组实现栈（java语言实现）

原文链接：

http://huangyunbin.iteye.com/blog/1354140

package com.zby.test;

public class Stack {
	private Object[] stack;
	private int size;
	private Stack(){
		this(10);
	}
	private Stack(int len) {
		stack = new Object[len];
	}
	
	public int size() {
		return size;
	}
	//返回栈的容量
	public int capacity() {
		return stack.length;
	}
	
	//实现动态数组
	public void ensureCapacity() {
		if(size() == capacity()) {
			Object[] newStack = new Object[size() * 3 / 2 + 1];
			System.arraycopy(stack, 0, newStack, 0, size());
			stack = newStack;
		}
	}
	
	//入栈
	public void push(Object o) {
		size++;
		ensureCapacity();
		stack[size - 1] = o;
	}
	
	//判空
	public boolean isEmpty() {
		return size == 0;
	}
	
	//出栈
	public Object pop() {
		if(isEmpty()) {
			throw new ArrayIndexOutOfBoundsException("不能为空");
		}
		
		Object o = stack[--size];
		stack[size] = null;
		return o;
	}
	
   public static void main(String[] args) {  
        Stack stack = new Stack(3);  
        String[] data = new String[] { "a", "b", "c" };  
        for (int i = 0; i < data.length; i++) {  
                stack.push(data[i]);  
                System.out.println(data[i] + "");  
        }  
        System.out.println("***********");  
        while (!stack.isEmpty()) {  
            System.out.println(stack.pop() + "");  
        }
    } 
}