downlader-goroutine.go

package main
import "fmt"

//define the download() function
func download(value int, ch chan int) {
    sum :=0
    for i:=0; i <= value; i++ {
        sum +=i
    }

    ch <- sum
}   

func main() {
    ch1 := make(chan int)
    ch2 := make(chan int)
    ch3 := make(chan int)

    var s1, s2, s3 int
    fmt.Scanln(&s1)
    fmt.Scanln(&s2)
    fmt.Scanln(&s3)

    go download(s1, ch1)
    go download(s2, ch2)
    go download(s3, ch3)

    //output the sum of all results
    fmt.Println(<-ch1 + <-ch2 + <-ch3)
}