update book code

eBook/exercises/chapter_14/goroutine_select.go

@@ -0,0 +1,31 @@
+// Q20b_goroutine.go
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func tel(ch chan int, quit chan bool) {
+	for i:=0; i < 15; i++ {
+		ch <- i
+	}
+	quit <- true
+}
+
+func main() {
+	var ok = true
+	ch := make(chan int)
+	quit := make(chan bool)
+
+	go tel(ch, quit)
+	for ok {
+		select {
+			case i:= <-ch:
+				fmt.Printf("The counter is at %d\n", i)
+			case <-quit:
+				os.Exit(0)
+		}
+	}
+}
+