5 Concurrency.1

5concurrency/channels.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"fmt"
+)
+
+func hello(done chan int) {
+	fmt.Println("goroutine worked")
+	done <- 101101
+}
+
+func main() {
+	fmt.Println("Channels are a typed conduit through which you can send and receive values with the channel operator, <-")
+	myChannel1 := make(chan int)
+
+	fmt.Println("When data is sent to a channel, the control is blocked in the send statement until some other Goroutine reads from that channel")
+	fmt.Println("Similarly, when data is read from a channel, the read is blocked until some Goroutine writes data to that channel")
+
+	go hello(myChannel1)
+	fmt.Println(<-myChannel1)
+	fmt.Println("Calling channels causes main function wait to terminate")
+
+	fmt.Println("end of main function")
+}

5concurrency/channels2.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func producer(chnl chan int) {
+	for i := 0; i < 10; i++ {
+		time.Sleep(100 * time.Millisecond)
+		chnl <- i
+	}
+	close(chnl)
+}
+
+func outer(chn2 chan int) {
+	for i := 10; i < 100; i++ {
+		chn2 <- i
+	}
+	close(chn2)
+}
+func main() {
+	ch, ch2 := make(chan int), make(chan int)
+	go producer(ch)
+	go outer(ch2)
+	for {
+		v, ok := <-ch
+		if ok == false {
+			v, ok2 := <-ch2
+			if ok2 == false {
+				break
+			}
+			fmt.Println("Received2 ", v, ok)
+			continue
+		}
+		fmt.Println("Received ", v, ok)
+	}
+	ch3 := make(chan int)
+	go producer(ch3)
+	for v := range ch3 {
+		fmt.Println("Received ", v)
+	}
+}

5concurrency/goroutines.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func printX() {
+	for i := 0; i < 100; i++ {
+		fmt.Print("X")
+	}
+}
+
+func printY() {
+	for i := 0; i < 100; i++ {
+		fmt.Print("Y")
+	}
+}
+
+func main() {
+	fmt.Println("a goroutine is a **lightweight** thread managed by the go runtime")
+
+	printX()
+	fmt.Println()
+	printY()
+	fmt.Println()
+	fmt.Println("you should see first X's then Y's")
+
+	time.Sleep(100 * time.Millisecond)
+	fmt.Println()
+	fmt.Println()
+
+	go printX()
+	go printY()
+	fmt.Println("you should see random X's and Y's, this because concurrency")
+
+	time.Sleep(1 * time.Second)
+	// wait for prevent main goroutine to terminate
+}