Ops Structs

Operator overloading structs และ traits ใน Rust ช่วยให้ custom types ใช้ operators มาตรฐานได้เหมือน built-in types เช่น +, -, *, [] ผ่าน traits ใน std::ops module

1. Arithmetic Operators

Arithmetic operators (+, -, *, /, %) สามารถ overload ได้ผ่าน traits Add, Sub, Mul, Div, Rem ทำให้ custom types เช่น vectors, matrices, หรือ complex numbers ใช้ operators เหล่านี้ได้

Basic Arithmetic Implementation

use std::ops::{Add, Sub, Mul, Div, Rem, Neg};

#[derive(Debug, Clone, Copy, PartialEq)]
struct Vector2D {
    x: f64,
    y: f64,
}

impl Add for Vector2D {
    type Output = Self;

    fn add(self, other: Self) -> Self::Output {
        Vector2D {
            x: self.x + other.x,
            y: self.y + other.y,
        }
    }
}

impl Sub for Vector2D {
    type Output = Self;

    fn sub(self, other: Self) -> Self::Output {
        Vector2D {
            x: self.x - other.x,
            y: self.y - other.y,
        }
    }
}

impl Neg for Vector2D {
    type Output = Self;

    fn neg(self) -> Self::Output {
        Vector2D {
            x: -self.x,
            y: -self.y,
        }
    }
}

// Scalar multiplication - different RHS type
impl Mul<f64> for Vector2D {
    type Output = Self;

    fn mul(self, scalar: f64) -> Self::Output {
        Vector2D {
            x: self.x * scalar,
            y: self.y * scalar,
        }
    }
}

fn main() {
    let a = Vector2D { x: 3.0, y: 4.0 };
    let b = Vector2D { x: 1.0, y: 2.0 };

    println!("a = {:?}", a);
    println!("b = {:?}", b);
    println!("a + b = {:?}", a + b);
    println!("a - b = {:?}", a - b);
    println!("-a = {:?}", -a);
    println!("a * 2.0 = {:?}", a * 2.0);
}