Golang协程WaitGroup

waitgroups.go

package main
 
import (
	"fmt"
	"sync"
	"time"
)
 
func w(id int) {
	fmt.Printf("Worker %d starting \n", id)
	time.Sleep(time.Second)
	fmt.Printf("Worker %d done \n", id)
}
func main() {
 
	var wg sync.WaitGroup
 
	for i := 1; i <= 5; i++ {
		wg.Add(i)
		i := i
		go func() {
			defer wg.Done()
			w(i)
		}()
	}
 
	wg.Wait()
}