package
main
//channel directions
//通道作为函数参数,你需要指明通道是作为发送还是接受。
//这种指明提高了程序类型的安全
import "fmt"
func ping(pings chan<- string, msg string) {
pings <- msg
}
// 通道作为参数
func pong(pings <-chan string, pongs chan<- string) {
msg := <-pings
pongs <- msg
}
func main() {
pings := make(chan string, 1)
pongs := make(chan string, 1)
ping(pings, "passed message")
pong(pings, pongs)
fmt.Println(<-pongs)
}