channel.go

package main

import (
	"fmt"
	"time"
	"log"
	"os"
)

func main() {
	f, err := os.Open("./cat.txt")
	defer f.Close()

	if err != nil {
		log.Fatal("Open file error: ", err)
	}

	bchan := make(chan []byte)

	go func() {
		defer close(bchan)

		for {
			b := make([]byte, 1)

			if _, err := f.Read(b); err == nil {
				bchan <- b
			} else {
				break
			}
		}
	}()
	loop:
		for {
			select {
			case b, ok := <-bchan:
				if ok {
					time.Sleep(100 * time.Millisecond)
					fmt.Printf("%s",b)
				} else {
					fmt.Println()
					break loop;
				}
			}
		}
	fmt.Println("main is eixt.")
}