package mainimport "fmt"func main() {	done := make(chan int, 10)	for i := 0; i < cap(done); i++ {		go func(j int) {			fmt.Println("你好，世界" + fmt.Sprintf("%v", j))			done <- 1		}(i)	}	//等待N个后台线程完成	for i := 0; i < cap(done); i++ {		<-done	}}

package mainimport (	"sync"	"fmt")func main() {	var wg sync.WaitGroup	for i := 0; i < 10; i++ {		wg.Add(1)		go func(j int) {			fmt.Println("你好，世界" + fmt.Sprintf("%v", j))			wg.Done()		}(i)	}	wg.Wait()}