projecteuler.net/001/main.rs

// https://projecteuler.net/problem=1 

fn main() {
    let mut sum = 0;
    for n in 1..= 999 {
        if n % 3 == 0 {
            sum += n;
        }
        if n % 5 == 0 && n % 3 != 0 {
            sum += n;
        }
    }
    println!("{}", sum);
}