add: switch statement exercises

12-switch/exercises/03-convert/solution/main.go

@@ -0,0 +1,46 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+const (
+	usage       = "Usage: [username] [password]"
+	errUser     = "Access denied for %q.\n"
+	errPwd      = "Invalid password for %q.\n"
+	accessOK    = "Access granted to %q.\n"
+	user, user2 = "jack", "inanc"
+	pass, pass2 = "1888", "1879"
+)
+
+func main() {
+	args := os.Args
+
+	if len(args) != 3 {
+		fmt.Println(usage)
+		return
+	}
+
+	u, p := args[1], args[2]
+
+	// More readable, right? 👍
+	switch {
+	case u != user && u != user2:
+		fmt.Printf(errUser, u)
+	case u == user && p == pass:
+		// notice this one (no more duplication)
+		fallthrough
+	case u == user2 && p == pass2:
+		fmt.Printf(accessOK, u)
+	default:
+		fmt.Printf(errPwd, u)
+	}
+}