van sickle fan out fan in

GoesToEleven · GoesToEleven · commit 9014e362aba3 · 2016-01-27T15:35:13.000-08:00
diff --git a/22_go-routines/13_channels_fan-out_fan-in/10_van-sickle_fan-out_fan-in/main.go b/22_go-routines/13_channels_fan-out_fan-in/10_van-sickle_fan-out_fan-in/main.go
@@ -0,0 +1,70 @@
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+
+	in := gen()
+	out := make(chan int)
+
+	// FAN OUT
+	// Multiple functions reading from the same channel until that channel is closed
+	// Distribute work across multiple functions (ten goroutines) that all read from in.
+	fanOut(in, 10, out)
+
+	// FAN IN
+	// multiplex multiple channels onto a single channel
+	// merge the channels from c0 through c9 onto a single channel
+	go func() {
+		for v := range out {
+			fmt.Println(v)
+		}
+	}()
+
+	var a string
+	fmt.Scanln(&a)
+}
+
+func gen() <-chan int {
+	out := make(chan int)
+	go func() {
+		for i := 0; i < 10; i++ {
+			for j := 3; j < 13; j++ {
+				out <- j
+			}
+		}
+		close(out)
+	}()
+	return out
+}
+
+func fanOut(in <-chan int, n int, out chan<- int) {
+	for i := 0; i < n; i++ {
+		factorial(in, out)
+	}
+}
+
+func factorial(in <-chan int, out chan<- int) {
+	go func() {
+		for n := range in {
+
+			out <- fact(n)
+		}
+	}()
+}
+
+func fact(n int) int {
+	total := 1
+	for i := n; i > 0; i-- {
+		total *= i
+	}
+	return total
+}
+
+/*
+This code was provided by my friend, Mike Van Sickle
+He is an awesome programmer, an awesome Go programmer, and an awesome teacher
+Check out his courses on pluralsight to learn more about Go!
+*/
