java用数组实现栈

http://zhidao.baidu.com/question/273136809.html

public class Stack {private Object[] stack;//这个不需要;//private int top = 0; //初始化栈顶//这个也不需要;//写一个栈出来,最好是可以动态的,可以自己改变大小的,即数组的长度;//private int size = 0; // 初始化大小//元素个数;private int size;//默认长度为10;public Stack(){this(10);}//也可以自己设置长度,即容量;public Stack(int len){stack = new Object[len];}//返回元素个数;public int size(){return size;}//返回数组长度,即容量;public int capacity(){return stack.length;}//实现动态的数组;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;}/*public void push(Object object) {if (isFull()) {System.out.println("栈满!  入栈失败");}stack[top++] = object;}*///判空;public boolean isEmpty(){return size == 0;}//出栈;public Object pop(){//首先要判空;if(isEmpty()){throw new ArrayIndexOutOfBoundsException("不能为空");}Object o = stack[--size];stack[size] = null;return o;}/*// 出栈public Object pop() {Object object = stack[--top];stack[top] = null;return object;}*//*// 计算栈当前大小public int size() {return top;}// 判断是否是空栈public boolean isEmpey() {return top == 0;}// 判断是否栈满public boolean isFull() {return top >= size;}public Stack(int size) {this.size = size;}*/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() + "");}//}     }}