go chan 入门代码

package main

import (
	"fmt"
	"sync"
	"time"
)

// 生产数据
func producer(num ...int)(ret<-chan int) {
	out:=make(chan int)
	go func() {
		defer close(out)
		for k,v:=range num {
			fmt.Printf("我在生产第%d个数据\n",k)
			out<-v
			fmt.Printf("生产第%d个数据完成\n",k)
		}
	}()
	ret=out
	return
}

// 从通道获取数据，计算数据
func square(inCh <-chan int) (ret <-chan int) {
	out:=make(chan int)
	go func() {
		defer close(out)
		for n:=range inCh{
			out<-n*n
			time.Sleep(1*time.Second)
		}
	}()
	ret=out
	return
}

// 给通道启动协程
func merge(cs ...<-chan int)(ret <-chan int)  {
	out:=make(chan int,100)
	var wg sync.WaitGroup
	collect:= func(in<-chan int) {
		defer wg.Done()
		for n:=range in{
			out<-n
		}
	}

	wg.Add(len(cs))

	for k,n:=range cs{
		fmt.Printf("我在给执行第%d个协程\n",k)
		go collect(n)
		fmt.Printf("执行第%d个协程完成\n",k)
	}

	go func() {
		wg.Wait()
		close(out)
	}()
	ret=out
	return
}
func main()  {
	in:=producer(0,1,2,3,4,5,6,7,8,9,10)
	ch1:=square(in)
	ch2:=square(in)
	ch3:=square(in)
	ch4:=square(in)
	ch5:=square(in)
	// 拿到数据结果
	for ret:=range merge(ch1,ch2,ch3,ch4,ch5){
		time.Sleep(1*time.Second)
		fmt.Printf("%3d\n",ret)
	}

}