package main
import "fmt"
func sum(a []int, c chan int) {
    sum := 0
    for _, v := range a {
        sum += v
    }
    c <- sum  // send sum to c
}
func main() {
    a := []int{7, 2, 8, -9, 4, 0}
        c := make(chan int)
    go sum(a[:len(a)/2], c)
    go sum(a[len(a)/2:], c)
        x, y := <-c, <-c  // receive from c
    fmt.Println(x, y, x + y)
}