advent_of_code/src/main.rs

use std::env;

fn main() {
    let day = match env::args().nth(1) {
        Some(arg) => arg.parse().unwrap(),
        None => 1
    };

    let result = match day {
        1 => advent_of_code::aoc01::both("./inputs/01-01.txt"),
        2 => advent_of_code::aoc02::both("./inputs/02-01.txt"),
        _ => Err(format!("unsupported day {}", day).into()),
    };

    match result {
        Ok(_) => (),
        Err(e) => println!("Error executing day {}: {}", day, e),
    }

}