use std::env;
use terbilang;
fn get_number_arg(args: &mut env::Args) -> Result<i64, String> {
let mut args = args.take(2);
let prog_name = args.next().unwrap();
match args.next() {
Some(arg) => match arg.parse::<i64>() {
Ok(number) => Ok(number),
Err(x) => Err(format!("{} `{}`", x, arg)),
},
_ => Err(format!("usage: {} <number>", prog_name)),
}
}
fn main() -> Result<(), Box<dyn std::error::Error>> {
let number: i64 = get_number_arg(&mut env::args())?;
let t = terbilang::terbilang(&number);
println!("number: {}, terbilang: {}", number, t);
Ok(())
}