package org.example;

import java.util.concurrent.CountDownLatch;

public class App8 {
    public static int num=0;

    public static void main(String[] args) throws InterruptedException {
        Thread[] threads=new Thread[100];
        CountDownLatch latch=new CountDownLatch(threads.length);
        for (int i = 0; i < threads.length; i++) {
            threads[i]=new Thread(() -> {
                for (int j = 0; j < 10000; j++) {
                    //此处需要加上synchronized同步代码块，来保证num++的原子性（通过上锁保证原子性）
//                    synchronized (App8.class){
                        num++;
//                    }
                }
                latch.countDown();
            });
        }
        for (Thread thread : threads) {
            thread.start();
        }
        //此处的目的保证num数值完整,如果latch.countDown();放在线程内for循环的前面的前面，会导致latch.await();提前放开，导致输出num变量的不准确性
        latch.await();
        System.out.println(num);

    }
}