数据结构之栈

package com.fz.song.stack;

/**
 * Created by sfz on 2017/8/29.
 */
public class MyStack {

    //长度
    private int size;
    //数组
    private int[] data;
    //栈顶
    private int top;

    public MyStack(int size) {
        this.size = size;
        data = new int[size];
        top = 0;
    }

    /**
     * 判断是否为空
     *
     * @return
     */
    public boolean isEmpty() {
        return 0 == top;
    }

    /**
     * 判满
     *
     * @return
     */
    public boolean isFull() {
        return (0 != size && size == top);
    }


    /**
     * 清空栈
     *
     * @return
     */
    public boolean cleanStack() {
        if (isEmpty()) {
            return false;
        } else {
            top = 0;
            return true;
        }
    }

    /**
     * 获取长度
     *
     * @return
     */
    public int length() {
        return top;
    }


    /**
     * 入栈
     *
     * @param elem
     * @return
     */
    public boolean push(int elem) {

        if (isFull()) {
            return false;
        } else {
            data[top] = elem;
            top++;
            return true;
        }
    }

    /**
     * 出栈
     *
     * @return
     */
    public int pop() throws Exception {

        if (isEmpty()) {
            throw new Exception("当前栈为空");
        } else {
            top--;
            int val = data[top];
            return val;
        }
    }

    /**
     * 遍历栈元素
     */
    public void each() {
        for (int i = 0; i < top; i++) {
            System.out.print(data[i] + "  ");
        }
        System.out.println("");
    }

}