Function init

chapter5/listing34/listing34.go:13–18

init is called before main.

()

// init is called before main.
func init() {
	if len(os.Args) != 2 {
		fmt.Println("Usage: ./example2 <url>")
		os.Exit(-1)
	}
}

// main is the entry point for the application.
func main() {