advent-of-code-2019/src/day_1/puzzle_1.rs

use std::fs::File;
use std::io::{BufRead, BufReader};
use std::path::Path;

pub fn solve() {
    let masses = read_masses("./src/day_1/puzzle_1.txt");
    let mut sum: f32 = 0.0;

    for mass in &masses {
        sum += (mass / 3.0).floor() - 2.0;
    }
    println!("sum: {}", sum);
}

fn read_masses(filename: impl AsRef<Path>) -> Vec<f32> {
    let file = File::open(filename).expect("no such file");
    let buffer = BufReader::new(file);

    buffer
        .lines()
        .map(|l| {
            l.expect("could not read line")
                .parse::<f32>()
                .expect("could not parse line")
        })
        .collect()
}