add.rs

use std::ops::Add;


/// Z^m number system
/// # Examples
/// ```
struct Mod<T: Modulo<T>> {
    modulo: T,
    i: T,
}

trait Modulo<T> {
    fn modulo(&self, n: T) -> T;
}

impl Modulo<i32> for i32 {
    fn modulo(&self, n: i32) -> i32 {
        if self.signum() != n.signum() {
            (-self) % n
        } else {
            self % n
        }
    }
}

impl<i32> Mod<i32> {
    fn new(modulo: i32, i: i32) -> Mod<i32> {
        let n = i.modulo(modulo);
        Mod {
            modulo: modulo,
            i: n,
        }
    }
}

impl Add for Mod<i32> {
	type Output = Mod<i32>;
    fn add(self, other: Mod<i32>) -> Mod<i32> {
        Mod::new(self.modulo, self.i + other.i)
    }
}



fn main() {
    let x = Mod::new(5, 3);
    let y = Mod::new(5, 2);
    let z = x + y;
	println!("{}", z.i);
}

err.txt

cargo run
   Compiling rustcallc v0.1.0 (file:///Users/kaiyin/Documents/workspace-eclipse-neon/rustcallc)
warning: unnecessary parentheses around `if` condition, #[warn(unused_parens)] on by default
  --> src/main.rs:18:12
   |
18 |         if (self.signnum() != n.signnum()) {
   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0046]: not all trait items implemented, missing: `Output`
  --> src/main.rs:36:1
   |
36 | impl Add for Mod<i32> {
   | ^ missing `Output` in implementation

error: aborting due to previous error