问题：启动10个goroutine,按顺序 打印出0-9。

Question

package main

import (
   "fmt"
   "sync"
   "sync/atomic"
   "time"
)

//使用sync.WaitGroup,启动10个goroutine,按顺序 打印0-9
var counter int32
func main(){
   var wg sync.WaitGroup
   wg.Add(10)
    var i int32
   for i = 0;i<10;i++{
      go printNum(&wg,i)
      time.Sleep(time.Nanosecond)
   }

}

func printNum(wg *sync.WaitGroup,i int32){
    if i == atomic.LoadInt32(&counter){
      fmt.Println(i)
      atomic.AddInt32(&counter,1)
      wg.Done()
   }
}

结果打印出1到9了。

各位大神，我写得是否符合题意？请帮忙点评，谢谢！

Answer 1

思路有点不对。

可以改为如下代码，自己比较一下差异。

package main
 
import (
   "fmt"
   "sync"
   "sync/atomic"
   "time"
)
 
//使用sync.WaitGroup,启动10个goroutine,按顺序 打印0-9
var counter int32
func main(){
   var wg sync.WaitGroup
   wg.Add(10)
    var i int32
   for i = 0;i<10;i++{
      go printNum(&wg,i)
      time.Sleep(time.Nanosecond)
   }
   wg.Wait()
 
}
 
func printNum(wg *sync.WaitGroup,i int32){
    for {
      if i == atomic.LoadInt32(&counter){
        fmt.Println(i)
        atomic.AddInt32(&counter,1)
        wg.Done()
        break
      }
      time.Sleep(time.Nanosecond)
    }
}