Initial commit

11-if/03-error-handling/03-atoi-error-handling/main.go

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+// 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"
+	"strconv"
+)
+
+func main() {
+	age := os.Args[1]
+
+	// Atoi returns an int and an error value
+	// So, you need to handle the errors
+
+	n, err := strconv.Atoi(age)
+
+	// handle the error immediately and quit
+	// don't do anything else here
+
+	if err != nil {
+		fmt.Println("ERROR:", err)
+
+		// quits/returns from the main function
+		// so, the program ends
+		return
+	}
+
+	// DO NOT DO THIS:
+	// else {
+	//   happy path
+	// }
+
+	// DO THIS:
+
+	// happy path (err is nil)
+	fmt.Printf("SUCCESS: Converted %q to %d.\n", age, n)
+}