多线程练习题

三个线程A,B,C,每个线程将自己在屏幕上打印五边，打印顺序为ABCABCABC....

class Print{
    private int flag=1; //1表示A，2表示B,3表示C
    private int count=0;
    public int getCount(){
        return count;
    }
    public synchronized void PrintA(){
        while(flag!=1){
            try{
                wait();
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
        System.out.print(Thread.currentThread().getName());
        flag=2;
        notifyAll();
        count++;
    }
    public synchronized void PrintB(){
        while(flag!=2){
            try{
                wait();
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
        System.out.print(Thread.currentThread().getName());
        flag=3;
        notifyAll();
        count++;
    }
    public synchronized void PrintC(){
        while(flag!=3){
            try{
                wait();
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
        System.out.print(Thread.currentThread().getName());
        flag=1;
        notifyAll();
        count++;
    }
}
class MyThread implements Runnable {
    private Print print;
    public MyThread(Print print) {
        this.print = print;
    }
    @Override
    public void run() {
        while (print.getCount() < 13) {  //调用A的次数  count
            if (Thread.currentThread().getName().equals("A")) {
                print.PrintA();
            }else if (Thread.currentThread().getName().equals("B")) {
                print.PrintB();
            }else if(Thread.currentThread().getName().equals("C")) {
                print.PrintC();
            }
        }
    }
}
public class Main{
    public static void main(String[] args) {
        Print print=new Print();
        MyThread mythread=new MyThread(print);
        new Thread(mythread,"A").start();
        new Thread(mythread,"B").start();
        new Thread(mythread,"C").start();
    }
}

 

两个线程，一个打印数字1-52，一个打印字母A-Z,打印顺序为12A34B56C....

class Print{
 private boolean flag=true;  //信号量
 private int count=1;
 public synchronized  void PrintNum(){
     if(flag==false){  //等待
         try{
             wait();
         }catch(InterruptedException e){
             e.printStackTrace();
         }
     }
     System.out.print(2*count-1);
     System.out.print(2*count);
     flag=false;  //执行打印字母方法
     notify();    //唤醒打印字母线程
 }
    public synchronized  void PrintChar(){
        if(flag==true){  //等待
            try{
                wait();
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
        System.out.print((char)('A'+count-1));
        flag=true;  //执行打印数字方法
        count++;
        notify();    //唤醒打印数字线程
    }
}
public class haha{
    public static void main(String[] args) {
        Print print=new Print();
        //打印数字线程
        new Thread(() ->{  //匿名内部类
            for(int i=0;i<26;i++){
                print.PrintNum();
            }
        }).start();
        //打印字母线程
        new Thread(()->{
            for(int i=0;i<26;i++){
                print.PrintChar();
            }
        }).start();
    }
}