update book code

eBook/examples/chapter_14/goroutine_select.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func main() {
+	ch1 := make(chan int)
+	ch2 := make(chan int)
+
+	go pump1(ch1)
+	go pump2(ch2)
+	go suck(ch1, ch2)
+
+	time.Sleep(1e9)
+}
+
+func pump1(ch chan int) {
+	for i := 0; ; i++ {
+		ch <- i * 2
+	}
+}
+
+func pump2(ch chan int) {
+	for i := 0; ; i++ {
+		ch <- i + 5
+	}
+}
+
+func suck(ch1, ch2 chan int) {
+	for {
+		select {
+		case v := <-ch1:
+			fmt.Printf("Received on channel 1: %d\n", v)
+		case v := <-ch2:
+			fmt.Printf("Received on channel 2: %d\n", v)
+		}
+	}
+}