Rust workshop part 1

workshop1.rs

use std::env;

struct Stats {
    max: f64,
    mean: f64,
    min: f64,
    size: u64,
    sum: f64,
}

fn main() {
    let numbers: Vec<f64> = env::args()
        .skip(1)
        .map(|n| n.parse::<f64>().unwrap())
        .collect();

    if numbers.is_empty() {
        eprintln!("Usage: cargo run <num>...");
        return;
    }

    let first = numbers[0];

    let initial = Stats {
        max: first,
        mean: first,
        min: first,
        size: 1,
        sum: first
    };

    if numbers.len() < 2 {
        println!("{}", format_result(initial));
        return;
    }

    let result = numbers[1..].fold(initial, |a: Stats, b: f64| Stats {
        max: a.max.max(b),
        mean: (a.sum + b) / (a.size as f64 + 1.0),
        min: a.min.min(b),
        size: a.size + 1,
        sum: a.sum + b
    });

    println!("{}", format_result(result));
}

fn format_result(result: Stats) -> String {
    return format!(
        "max: {}, mean: {}, min: {}, size: {}, sum: {}",
        result.max, result.mean, result.min, result.size, result.sum
    );
}