golang多个goroutinue顺序打印数字

code

一. 10个goroutinue顺序打印0-9

常规的做法是用10个channel来挨个控制，其实可以用原子包实现，相当于加锁

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func printInOrder() {
	wg := sync.WaitGroup{}
	var curr int32
	for i := int32(0); i < 10; i++ {
		wg.Add(1)
		go func(num int32) {
			defer wg.Done()
			for {
				if n := atomic.LoadInt32(&curr); n == num {
					fmt.Println(num)
					atomic.AddInt32(&curr, 1)
					break
				}
				time.Sleep(time.Nanosecond)
			}
		}(i)
	}

	wg.Wait()
}

二. 两个goroutinue分别打印奇偶数

同上，还是用原子包

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func printMix() {
	wg := sync.WaitGroup{}
	var curr int32
	wg.Add(2)
	go func() {
		defer wg.Done()
		for curr < 10 {
			if n := atomic.LoadInt32(&curr); n%2 == 1 {
				fmt.Println("A:", n)
				atomic.AddInt32(&curr, 1)
			} else {
				time.Sleep(time.Nanosecond)
			}
		}
	}()
	go func() {
		defer wg.Done()
		for curr < 10 {
			if n := atomic.LoadInt32(&curr); n%2 == 0 {
				fmt.Println("B:", n)
				atomic.AddInt32(&curr, 1)
			} else {
				time.Sleep(time.Nanosecond)
			}
		}
	}()

	wg.Wait()
}