Interfaces assignment2 and channels

channels/go.mod

@@ -0,0 +1,3 @@
+module channels
+
+go 1.17

channels/main.go

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+package main
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+)
+
+func main() {
+	urls := []string{
+		"https://google.com",
+		"https://facebook.com",
+		"https://golang.org",
+		"https://johannes-rothe.de",
+		"https://amazon.com",
+	}
+	c := make(chan string)
+	for _, url := range urls {
+		go checkURL(url, c)
+	}
+	for url := range c { // wait for the channel to return a value, then assign it to l
+		go func(url string) {
+			time.Sleep(2 * time.Second)
+			checkURL(url, c)
+		}(url)
+		//go checkURL(url, c)
+		//fmt.Println(<-c) // value through c is a blocking call
+	}
+}
+
+func checkURL(url string, c chan string) {
+	_, err := http.Get(url)
+	if err != nil {
+		fmt.Printf("%s might be down!\n", url)
+		c <- url
+		return
+	}
+	fmt.Printf("%s is up!\n", url)
+	c <- url
+}

interfaces_assignment2/go.mod

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+module interfaces_assignment2
+
+go 1.17

interfaces_assignment2/main.go

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+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		fmt.Printf("No filename given!\n Usage: %s <filename>\n", os.Args[0])
+		os.Exit(1)
+	}
+	filename := os.Args[1]
+	file, err := os.Open(filename)
+	if err != nil {
+		log.Fatal(err)
+		os.Exit(1)
+	}
+	io.Copy(os.Stdout, file)
+}

interfaces_assignment2/myfile.txt

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+Hello World!