Added go scheduler example

master_concurrent_go/ch01/main.go

@@ -2,7 +2,8 @@ package main
 
 import (
 	"fmt"
-	"sync"
+	"io/ioutil"
+	"runtime"
 	"time"
 )
 
@@ -12,27 +13,43 @@ type Job struct {
 	text string
 }
 
-func outputText(j *Job, wg *sync.WaitGroup) {
+func outputText(j *Job) {
-	defer wg.Done()
+	fileName := j.text + ".txt"
+	fileContents := ""
 	for j.i < j.max {
 		time.Sleep(1 * time.Millisecond)
+		fileContents += j.text
 		fmt.Println(j.text)
 		j.i++
 	}
+	err := ioutil.WriteFile(fileName, []byte(fileContents), 0644)
+	if err != nil {
+		panic("Something went awry")
+	}
 }
-
 func main() {
-	wg := new(sync.WaitGroup)
 	hello := new(Job)
-	world := new(Job)
 	hello.text = "hello"
 	hello.i = 0
 	hello.max = 3
+	world := new(Job)
 	world.text = "world"
 	world.i = 0
 	world.max = 5
-	go outputText(hello, wg)
+	go outputText(hello)
-	go outputText(world, wg)
+	go outputText(world)
-	wg.Add(2)
+	goSched()
-	wg.Wait()
+}
+
+func goSched() {
+	iterations := 10
+	for i := 0; i <= iterations; i++ {
+		go showNumber(i)
+	}
+	runtime.Gosched()
+	fmt.Println("Goodbye!")
+}
+
+func showNumber(num int) {
+	fmt.Println(num)
 }