我想使用两个线程打印斐波那契数列.像第一个数字应该由第一个线程打印，然后由第二个线程打印第二个数字，依此类推 [英] I want to print the fibonacci series using two threads. Like 1st number should be printed by 1st thread and then 2nd number by 2nd thread and so on

问题描述

我希望斐波那契数列由线程打印，该系列的第一个数字应由第一个线程打印，然后由第二个线程打印第二个数字，然后由第一个线程打印第三个，依此类推.

I want fibonacci series to be printed by threads and the 1st number of the series should be printed by 1st thread then 2nd number by 2nd thread then 3rd by 1st thread and 4th by 2nd and so on.

我通过使用数组尝试了此代码，例如使用线程打印数组元素，但我无法在线程之间切换.

I tried this code by using arrays like printing the array elements using thread but I am not able to switch between the threads.

class Fibonacci{
    void printFibonacci() {
       int fibArray[] = new int[10];
       int a = 0;
       int b = 1;
       fibArray[0] = a;
       fibArray[1] = b;
       int c;
       for(int i=2;i<10;i++) {
           c = a+b;
           fibArray[i] = c;
           a = b;
           b = c;
       }
       for(int i=0;i<10;i++) {
        if(Integer.parseInt(Thread.currentThread().getName())%2==0 && (i%2==0))
        {
            System.out.println("Thread " +Thread.currentThread().getName()+" "+fibArray[i]);
            try{
                wait();
            }catch(Exception e) {}
        }
        else if(Integer.parseInt(Thread.currentThread().getName())%2!=0 && (i%2!=0))
        {
            System.out.println("Thread " +Thread.currentThread().getName()+" "+fibArray[i]);
        }
     }
   }
}

public class FibonacciUsingThread {

    public static void main(String[] args) throws Exception {
        Fibonacci f = new Fibonacci();
        Thread t1 = new Thread(()->
        {
            f.printFibonacci();
        });
        Thread t2 = new Thread(()->
        {
            f.printFibonacci();
        });
        t1.setName("0");
        t2.setName("1");
        t1.start();
        t1.join();
        t2.start();
    }
}

推荐答案

代码中的以下行是 导致 t1 在 t2 开始之前完成.

The following line in your code is causing t1 to finish before t2 can start.

t1.join();

除此之外，您还需要在方法上进行同步，printFibonacci.

Apart from this, you need to synchronize on the method, printFibonacci.

你可以这样做:

class Fibonacci {
    synchronized void printFibonacci() throws InterruptedException {
        int fibArray[] = new int[10];
        int a = 0;
        int b = 1;
        fibArray[0] = a;
        fibArray[1] = b;
        int c;
        for (int i = 2; i < 10; i++) {
            c = a + b;
            fibArray[i] = c;
            a = b;
            b = c;
        }
        for (int i = 0; i < 10; i++) {
            String currentThreadName = Thread.currentThread().getName();
            if (currentThreadName.equals("1")) {
                if (i % 2 == 0) {
                    System.out.println("Thread " + Thread.currentThread().getName() + " " + fibArray[i]);
                    notify();
                } else {
                    wait();
                }
            } else if (currentThreadName.equals("0")) {
                if (i % 2 == 1) {
                    System.out.println("Thread " + Thread.currentThread().getName() + " " + fibArray[i]);
                    notify();
                } else {
                    wait();
                }
            }
        }
    }
}

public class Main {
    public static void main(String[] args) {

        Fibonacci f = new Fibonacci();
        Thread t1 = new Thread(() -> {
            try {
                f.printFibonacci();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });
        Thread t2 = new Thread(() -> {
            try {
                f.printFibonacci();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });
        t1.setName("0");
        t2.setName("1");
        t1.start();
        t2.start();
    }
}

输出:

Thread 1 0
Thread 0 1
Thread 1 1
Thread 0 2
Thread 1 3
Thread 0 5
Thread 1 8
Thread 0 13
Thread 1 21
Thread 0 34

这篇关于我想使用两个线程打印斐波那契数列.像第一个数字应该由第一个线程打印，然后由第二个线程打印第二个数字，依此类推的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！