Added closing channels

closingchannels/closingchannels.go

@@ -0,0 +1,46 @@
+package closingchannels
+
+import (
+	"fmt"
+	"math"
+	"math/rand"
+	"time"
+)
+
+func ClosingChannels() {
+	jobs := make(chan int, 5)
+	done := make(chan bool)
+
+	go func() {
+		for {
+			val, more := <-jobs
+
+			if more {
+				time.Sleep(time.Duration(rand.Intn(3)) * time.Second)
+				fmt.Printf("%d ^ %d is %f\n", val, 2, math.Pow(float64(val), 2))
+			} else {
+				fmt.Println("No more jobs, goroutine exiting")
+				done <- true
+				return
+			}
+		}
+	}()
+
+	for i := range 3 {
+		jobs <- i + 1
+	}
+	fmt.Println("Sent all jobs")
+
+	close(jobs)
+
+	<-done
+
+	_, more := <-jobs
+	if more {
+		fmt.Println("Uh-oh, jobs queue is not empty")
+	} else {
+		fmt.Println("Jobs queue is empty")
+	}
+
+	fmt.Println("Exiting")
+}