JAVA-使10个线程同时运行以增加计数器1-10

Question

I need 10 threads in JAVA to run simultaneously to increment counter from 1-10.

I have the code working. But, the counter is always in a different order.

public class Counter
{

    static Thread[] threads = new Thread[10];
    public static void main(String[] args)
    {
        Count c = new Count();
        for(int i=0;i<10;i++)
        {
            threads[i] = new Thread(c);
            threads[i].start();
        }

    }
}

public class Count implements Runnable {
    int n=1;

    @Override
    public void run() {
        System.out.println(n++);
    }

    public void showOutput(){
        System.out.println(n++);
    }

}

Output Example:2 4 3 1 5 9 8 6 7 10

Answer 1

Threads are asynchronous and work independently. There is no guanrantee of any order of execution of anything in different threads, unless there are some synchronization methods used . Your code works fine.

Answer 2

Use Join() function to run your threads in sync add the below code in your loop

try {
    threads[i].join();
} catch (InterruptedException e) {
    e.printStackTrace();
}

Hope this helps!

Thanks -vivek

Answer 3

You can use synchronized thread

@Override
public synchronized void run() {
    System.out.println(n++);
}