JAVA 多線程編程題

題目

編寫一個Java程序,該程序將啓動4個線程,其中3個是擲硬幣線程,1個是主線程。每個擲硬幣線程將連續擲出若干次硬幣(10次以內,次數隨機生成);主線程將打印出正面出現的總次數以及正面出現的概率。

難點

因爲要計算數量以及出現概率，所以必須將所有子線程內的數據同步到主線程內。

源代碼

Coin.java

package com.web.homework03;


public class Coin{

    public static void main(String[] args) throws InterruptedException {
        test test = com.web.homework03.test.getTest();
        Thread[] trr = new Thread[3];
        for (int i = 0; i < 3; i++) {
            trr[i] = new Thread(new Roll(test), "線程" + (i + 1));
        }
        for (Thread thread : trr) {
            thread.start();
        }
        for (Thread thread : trr) {
            thread.join();
        }
        System.out.println("正面總次數爲："+test.getRoll());
        System.out.println("正面總次數爲："+test.getRandoms());
        System.out.println("出現正面的概率爲："+(double)test.getRoll()/test.getRandoms());
    }
}

Roll.java

package com.web.homework03;

public class Roll implements Runnable{
    private test test01;
    public Roll(test test){
        this.test01 = test;
    }
    @Override
    public void run() {
        test01.method();
    }
}

test.java

package com.web.homework03;

import java.util.Random;

public class test {
    private int randoms;
    private int roll;

    public int getRandoms() {
        return randoms;
    }

    public void setRandoms(int randoms) {
        this.randoms = randoms;
    }

    public int getRoll() {
        return roll;
    }

    public void setRoll(int roll) {
        this.roll = roll;
    }

    private test() {
    }
    private static final test test = new test();
    public static test getTest() {
        return test;
    }
    public synchronized void method() {
        Random random = new Random();
        int times = random.nextInt(10);
        randoms += times;
        for (int i =0;i<times;i++){
            if (random.nextBoolean()){
                roll++;
            }
        }
    }
}