conc.go

package main

import (
	"fmt"
)

func main() {
	c := make(chan int, 10)

	go task1(c)
	go task2(c)
	go task3(c)

	sum := 0

	sum += <-c
	sum += <-c
	sum += <-c

	fmt.Println(sum)
}

func task1(c chan int) {
	c <- 1
}

func task2(c chan int) {
	c <- 2
}

func task3(c chan int) {
	c <- 3
}

conc.scala

package main

import scala.concurrent.{Await, Future}
import scala.concurrent.duration._
import scala.concurrent.ExecutionContext.Implicits.global

object Main extends App {

  def task1: Future[Int] = Future { 1 }

  def task2: Future[Int] = Future { 2 }

  def task3: Future[Int] = Future { 3 }

  val f1 = task1
  val f2 = task2
  val f3 = task3

  val sumF =
    for {
      a <- f1
      b <- f2
      c <- f3
    } yield a + b + c

  val sum = Await.result(sumF, Duration.Inf)
  println(sum)
}