基本思想：使用两个栈，一个负责存入数据，另一个专门负责弹出数据

package package1128;

import java.util.Stack;

/**
 * @author CHENG 2018/11/28
 */

public class MyQueue {

    private Stack stackIn, stackOut;

    /**初始化*/
    public MyQueue() {
        stackIn = new Stack();
        stackOut = new Stack();
    }

    /**push操作*/
    public void push(int x) {
        stackIn.push(x);
    }

    /**pop操作*/
    public int pop() {
        /**如果stackOut为空，则转移栈中的数据*/
        if(stackOut.size() == 0) {
            while (!stackIn.empty()) {
                int temp = (int) stackIn.pop();
                stackOut.push(temp);
            }
        }
        /**非空，直接返回数据*/
        return (int) stackOut.pop();
    }

    /**peek操作*/
    public int peek() {
        if(stackOut.size() == 0) {
            while (!stackIn.empty()) {
                int temp = (int) stackIn.pop();
                stackOut.push(temp);
            }
        }
        return (int) stackOut.peek();
    }

    /**empty判断*/
    public boolean empty() {
        if(stackIn.size() == 0 && stackOut.size() == 0) return true;
        return false;
    }

    /**测试*/
    public static void main(String[] args) {
        MyQueue queue = new MyQueue();

        queue.push(2);
        queue.push(3);

        System.out.println(queue.pop());
        System.out.println(queue.empty());
        System.out.println(queue.pop());
        System.out.println(queue.empty());
    }

}