大家来解惑--这段代码有啥问题？

javasgl · · 2912 次点击

``` package main import ( "fmt" "time" ) func main() { limiter := make(chan bool, 10) for i := 0; i < 100; i++ { limiter <- true go download(i, limiter) } } func download(index int, limiter chan bool) { time.Sleep(1 * time.Second) fmt.Println("start to download :", index) <-limiter } ``` 上面这段代码执行结果为什么最大打印值直到 89 ？当把 ``` time.Sleep(1 * time.Second) fmt.Println("start to download :", index) ``` 两行上下调换之后，变成以下的代码： ``` fmt.Println("start to download :", index) time.Sleep(1 * time.Second) ``` 就能正常打印到 99 了？

阅读全文

查看全部 32 个评论

yuanrr

```go package main import ( "fmt" "sync" "time" ) var wg sync.WaitGroup func main() { limiter := make(chan int, 10) wg.Add(20) //这里个数要和下载任务个数一致 for i := 0; i < 20; i++ { limiter <- i go download(limiter) } wg.Wait() fmt.Println("结束的收尾工作") } func download(limiter chan int) { defer wg.Done() i, ok := <-limiter if !ok { fmt.Println("all download") return } time.Sleep(1 * time.Second) fmt.Println("start to download :", i) } ```

评论于 2017-09-19 07:22:35

#29

更多评论