Range over channel exercise (#170)

Author: kaushalyap

internal/exercises/catalog.yaml

@@ -236,7 +236,11 @@ concepts:
     - Use `sync/atomic` package to create and increment atomic counter.
     - Launch 10,000 anonymous go routines that simultaneously increment the counter.
     - Use WaitGroups to wait for all go routines to finish. 
-
+- slug: 45_range_over_channels
+  title: Range over channels
+  test_regex: ".*"
+  hints:
+    - Use `for i := range ch {...}` syntax to range over a channels. 
 
 projects:
 - slug: 101_text_analyzer

internal/exercises/solutions/45_range_over_channels/range_over_channels.go

@@ -0,0 +1,19 @@
+package range_over_channels
+
+func getEvents(ch chan<- int) {
+	for i := range 10 {
+		ch <- i
+	}
+	close(ch)
+}
+
+func processStream() int {
+	ch := make(chan int)
+	go getEvents(ch)
+
+	sum := 0
+	for event := range ch {
+		sum += event
+	}
+	return sum
+}

internal/exercises/templates/45_range_over_channels/range_over_channels.go

@@ -0,0 +1,20 @@
+package range_over_channels
+
+// Assume case where you receive stream of events
+// through a channel till it is closed.
+// And you process those events as they come through.
+
+func getEvents(ch chan<- int) {
+	for i := range 10 {
+		ch <- i
+	}
+	close(ch)
+}
+
+// TODO: 1. Range over the channel, calculate the sum from events and return it.
+func processStream() int {
+	ch := make(chan int)
+	go getEvents(ch)
+
+	return 0
+}

internal/exercises/templates/45_range_over_channels/range_over_channels_test.go

@@ -0,0 +1,14 @@
+package range_over_channels
+
+import (
+	"testing"
+)
+
+func TestRangeOverChannels(t *testing.T) {
+	got := processStream()
+	want := 45
+
+	if got != want {
+		t.Fatalf("Expected %v, got %v", want, got)
+	}
+}