package main

import (
    "fmt"
    "sync"
)

func PrintABC() {
    var wg sync.WaitGroup
    cha := make(chan int, 1)
    defer close(cha)
    chb := make(chan int, 1)
    defer close(chb)
    chc := make(chan int, 1)
    defer close(chc)

    wg.Add(3)
    go PrintA(&wg, cha, chb)
    go PrintB(&wg, chb, chc)
    go PrintC(&wg, chc, cha)
    cha <- 1
    wg.Wait()
}

func PrintA(wg *sync.WaitGroup, cha, chb chan int) {
    count := 0
    for {
        if count >= 10 {
            fmt.Println("A quit")
            wg.Done()
            return
        }
        //
        <-cha
        fmt.Println("A", count)
        count++
        chb <- 1
    }
}

func PrintB(wg *sync.WaitGroup, chb, chc chan int) {
    count := 0
    for {
        if count >= 10 {
            fmt.Println("B quit")
            wg.Done()
            return
        }
        //
        <-chb
        fmt.Println("B")
        count++
        chc <- 1
    }
}

func PrintC(wg *sync.WaitGroup, chc, cha chan int) {
    count := 0
    for {
        if count >= 10 {
            fmt.Println("C quit")
            wg.Done()
            return
        }
        //
        <-chc
        fmt.Println("C")
        count++
        cha <- 1
    }
}