Function hello2

golang/go-study/go语言基础/并发/goroutine/启动多个goroutine.go:10–13

(i int)

var wg2 sync.WaitGroup

func hello2(i int) {
	defer wg2.Done() // goroutine结束就登记-1
	fmt.Println("hello", i)
}

func main() {
	for i := 0; i < 10; i++ {