题目: 使用 goroutine 和 channel 实现一个计算int64随机数各位数和的程序，例如生成随机数61345，计算其每个位数上的数字之和为19。
- 开启一个 goroutine 循环生成int64类型的随机数，发送到 jobChan
- 开启24个 goroutine 从jobChan中取出随机数计算各位数的和，将结果发送到resultChan
- 主 goroutine 从resultChan取出结果并打印到终端输出
package main
import (
"fmt"
"math/rand"
"runtime"
"time"
)
func main() {
numChan := make(chan int, 24)
resChan := make(chan int)
for i := 0; i < 24; i++ {
go func() {
for num := range numChan {
if check19(num) {
resChan <- num
break
}
}
}()
}
FOR:
for {
select {
case res := <-resChan:
fmt.Println(res)
close(numChan)
close(resChan)
break FOR
default:
fmt.Println("runtime.NumGoroutine() =", runtime.NumGoroutine(), time.Now())
numChan <- genNum()
}
}
}
func genNum() int {
rand.Seed(time.Now().UnixNano())
return rand.Intn(10000)
}
func check19(num int) bool {
time.Sleep(time.Second * 10)
sum := 0
for num >= 10 {
sum += num % 10
num /= 10
}
sum += num
return sum == 19
}
go channel(con-currency) 学习资料: medium Anatomy of Channels in Go - Concurrency in Go