Greetings

extern crate chrono;
use chrono::{Timelike, Utc};

fn main() {
    println!("{}, {name}", time_of_the_day_greetings(), name="John");
}

fn time_of_the_day_greetings() -> &'static str{
    let now = Utc::now();
    let hour = now.hour();

    if hour < 12 {
        "Good morning"
    } else if hour < 18 {
        "Good afternoon"
    } else {
        "Good evening"
    }
}