go并发

package main

import "fmt"
import "runtime"

//go并发程序
func say(s string) {
    for i := 0; i < 5; i++ {
        runtime.Gosched() //系统让出时间片
        fmt.Println(s)
    }
}

func main() {
    go say("world") //开启一个新的goroutine执行程序
    say("hello")
}


//利用channl通信
package main

import "fmt"

func sum(a []int, c chan int) {
    sum := 0
    for _, v := range a {
        sum += v
    }
    c <- sum
}
func main() {
    a := []int{1, 2, 5, 23}
    c := make(chan int)
    go sum(a[:len(a)/2], c)
    go sum(a[len(a)/2:], c)
    x, y := <-c, <-c
    fmt.Println(x, y, x+y)
}