栈

package com.zhb.corejava.util;
public class Stack<E> {
    private E[] elementData;
    private int top;

    private int count;

    @SuppressWarnings("unchecked")
    public Stack(int size) {
        this.elementData = (E[]) new Object[size];
        top = -1;
        count = 0;
    }
    public Stack() {
        this(10);
    }

    /**
     * 返回堆栈长度
     * @return
     */
    public int getSize(){
        return elementData.length;
    }

    /**
     * 返回栈中元素的个数
     * @return
     */
    public int getElementCount() {
        return count;
    }

    /**
     * 判栈空
     * @return
     */
    public boolean isEmpty(){
        return top == -1;
    }

    /**
     * 判栈满
     * @return
     */
    public boolean isFull(){
        return top == (elementData.length-1);
    }

    /**
     * 入栈操作
     * @param object
     */
    public void push(E object){
        if(isFull()){
            throw new RuntimeException("栈已经满");
        }else{
            elementData[++top] = object;
            count++;
        }
    }

    /**
     * 出栈操作，并返回被出栈的元素
     * @return
     */
    public E pop(){
        if(isEmpty()){
            throw new RuntimeException("栈是空的");
        }else{
            count--;
            return elementData[top--];
        }
    }
/**
     * 返回栈顶元素
     * @return
     */
    public E peek(){
        if(isEmpty()){
            throw new RuntimeException("栈是空的");
        }else{
            return elementData[top];
        }
    }
}