package main

import "fmt"

func main() {

	pings := make(chan string, 1)

	pongs := make(chan string, 1)

	ping(pings, "passwd message")

	pong(pings, pongs)

	fmt.Println(<-pongs)

}

//只写chan pings

func ping(pings chan<- string, msg string) {

	pings <- msg

}

//只读chan pings

func pong(pings <-chan string, pongs chan<- string) {

	msg := <-pings

	pongs <- msg

}