package main

import (
	"fmt"
	"time"
)

func main() {
	c := make(chan struct{})

	go ping(c)
	go pong(c)
	
	// start the game
	c <- struct{}{}

	time.Sleep(time.Second * 10)
	// stop the game after 10 sec
	<-c
}

func play(c chan struct{}, player string) {
	<-c
	fmt.Println(player)
	time.Sleep(time.Second)
	c <- struct{}{}
}

func ping(c chan struct{}) {
	for {
		play(c, "Ping")
	}
}

func pong(c chan struct{}) {
	for {
		play(c, "Pong")
	}
}