enum Error {
    AddOverflow,
    ProdOverflow,
}

fn main() {
    let res = tester();

    match res {
        Ok(_) => println!("success"),
        Err(e) => {
            match e {
                Error::AddOverflow => panic!("add_overflow"),
                Error::ProdOverflow => panic!("prod_overflow")
            }
        }
    }
}

fn tester() -> Result<bool, Error> {
    let x: u32 = u32::MAX;
    let y: u32 = 1;

    let mut res: u32;

    res = add(y, y)?;
    println!("{res}");

    res = prod(x, x)?;
    println!("{res}");

    Ok(true)
}

fn add(x: u32, y: u32) -> Result<u32, Error> {
    let sum: u64 = (x as u64) + (y as u64);

    if sum > (u32::MAX as u64) {
        return Err(Error::AddOverflow);
    }

    Ok(sum as u32)
}

fn prod(x: u32, y: u32) -> Result<u32, Error> {
    let prod: u64 = (x as u64) * (y as u64);

    if prod > (u32::MAX as u64) {
        return Err(Error::ProdOverflow);
    }

    Ok(prod as u32)
}