golang 实现goroutine顺序输出

golang 实现goroutine顺序输出

原理：waitgroup 保证协程阻塞，执行完毕。chan是有序的（先进先出）保证循序执行。

func main() {
	str := make([]string, 0)
	//str1 := make([]string, 0)
	str = append(str, "1")
	str = append(str, "2")
	str = append(str, "3")
	str = append(str, "4")
	str = append(str, "5")
	wg := sync.WaitGroup{}
	result := make(map[int]string)
	sli := make([]int, 0)
	for i, c := range str {
		sli = append(sli, i)
		ch := make(chan string)
		wg.Add(1)

		go func(ch <-chan string, index int, res map[int]string) {
			key := <-ch
			//fmt.Println(key)
			//str1 = append(str1, key)
			res[index] = key
			wg.Done()
		}(ch, i, result)
		ch <- c
	}

	wg.Wait()

	for i := range sli {
		fmt.Println(result[i])
	}