迅雷笔试题

启动三个线程，循环打印出ABCABC....

代码实现如下：

public class ABC {

    public static void main(String[] args) {
        Lock lock=new Lock();
        MyThread t1=new MyThread("A", lock,10);
        MyThread t2=new MyThread("B", lock,10);
        MyThread t3=new MyThread("C", lock,10);
        new Thread(t1).start();
        new Thread(t2).start();
        new Thread(t3).start();
    }
    
}
//线程
class MyThread implements Runnable{

    String key=null;
    Lock lock=null;
    int num=0;
    public MyThread(String k,Lock l,int n) {
    key=k;
    lock=l;
    num=n;
    }
    @Override
    public void run() {
        while(num>0){
            synchronized (lock) {
                if(key==lock.queue.getFirst())    
                {
                System.out.print(key);
                lock.next();
                num--;
                }}
        }
    }
}
//锁功能
class Lock{
    LinkedList<String>queue;//模仿循环队列
    Lock(){
        queue=new LinkedList<String>();
        queue.add("A");
        queue.add("B");
        queue.add("C");        
    }
     void next(){
        String h=queue.poll();
        queue.add(h);
    }
    
}