a demo for usage of goroutin, channel, select

goroutin-channel-select.go

package main

import (
	"fmt"
	"time"
)

func main() {
	timeout := make(chan bool, 1)
	ch := make(chan int)
	hello := make(chan string)

	go func() {
		time.Sleep(1e9)
		timeout <- true
		ch <- 1
	}()

	go func() {
		time.Sleep(10 * 1e9)
		hello <- "hello world"
	}()

	for {
		time.Sleep(1e8)
		select {
		case <-ch:
			fmt.Println("\nch channel")
		case <-timeout:
			fmt.Println("\ntimeout!")
		case str := <-hello:
			fmt.Println("\n", str)
		default:
			fmt.Printf(".")
		}
	}
}