复数在锈蚀中的实现
复数在锈蚀中的实现
提问于 2023-05-09 12:01:14
我正在学习面向对象的编程在锈蚀。我为复数创建了自己的结构。请你回顾并回答我的问题：
- 是否可以实现类似C++的默认构造函数？我想用
let c0 = my_math::Complex::default();代替let c0: Complex;。 - 为什么我要实现
PartialEq而不是Eq？ - 我为什么要实现
type Output = Complex;？我已经有-> Complex了。
mod my_math {
use std::fmt;
use std::ops;
use std::cmp::PartialEq;
pub struct Complex {
// Complex numbers (real, image * i)
pub real: i32,
pub imaginary: i32
}
impl Complex {
pub fn new(real: i32, imaginary: i32) -> Complex {
Complex {real: real, imaginary: imaginary}
}
}
impl Default for Complex {
fn default() -> Self {
Complex { real: 0, imaginary: 0}
}
}
impl fmt::Display for Complex {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "({}, {}i)", self.real, self.imaginary)
}
}
impl ops::Add for Complex {
type Output = Complex;
fn add(self, rhs: Complex) -> Complex {
Complex {real: rhs.real + self.real, imaginary: rhs.imaginary + self.imaginary}
}
}
impl ops::Sub for Complex {
type Output = Complex;
fn sub(self, rhs: Complex) -> Complex {
Complex {real: self.real - rhs.real, imaginary: self.imaginary - rhs.imaginary}
}
}
impl ops::Mul for Complex {
type Output = Complex;
fn mul(self, rhs: Complex) -> Self::Output {
Complex {
real: self.real * rhs.real - self.imaginary * rhs.imaginary,
imaginary: self.real * rhs.imaginary + self.imaginary * rhs.real
}
}
}
impl PartialEq for Complex {
fn eq(&self, other: &Self) -> bool {
self.real == other.real && self.imaginary == other.imaginary
}
}
}
fn main() {
let c0 = my_math::Complex::default();
assert!(c0.real == 0);
assert!(c0.imaginary == 0);
let c1 = my_math::Complex{real: 1, imaginary: 10};
let c2 = my_math::Complex::new(2, 20);
let c3 = c1 + c2;
let c3_expected = my_math::Complex::new(3, 30);
assert!(c3 == c3_expected);
println!("{}", c3);
} 回答 1
Code Review用户
回答已采纳
发布于 2023-05-09 13:59:29
派生PartialEq (可能还有Eq )和Default，而不是手动实现
#[derive(PartialEq, Default)]
pub struct Complex {
// Complex numbers (real, image * i)
pub real: i32,
pub imaginary: i32
}这简化了代码。
删除use std::cmp::PartialEq;
这是多余的- PartialEq在前奏曲里。
总是为您的类型#[derive(Debug)]提供
这允许以程序员-convienent格式打印它们。
为Complex
实现Clone和Copy
#[derive(Clone, Copy)]
pub struct Complex {
// Complex numbers (real, image * i)
pub real: i32,
pub imaginary: i32
}这允许在需要时复制Complex，另外，实现Copy允许使用标准库类型进行一些优化。
在适当的时候使用assert_eq!()将assert!(x == y)替换为assert_eq!(x, y)。这将打印x和y，以防断言失败。这要求他们实现Debug。
也实现Eq
我不知道你为什么决定不去实现它；你应该尽可能地去实现它。
用rustfmt
格式化代码
这使得您的代码遵循正式的锈蚀风格。
使用derive_more
这是不必要的(例如，我不会这样做)，但是如果您可以引入依赖项，您可以避免手动实现操作系统，甚至可以避免使用new实现derive_more：
#[derive(
Debug,
Clone,
Copy,
PartialEq,
Eq,
Default,
derive_more::Constructor,
derive_more::Add,
derive_more::Sub,
)]
pub struct Complex {
// Complex numbers (real, image * i)
pub real: i32,
pub imaginary: i32,
}将Complex中的注释更改为文档注释
这将更好地记录结构。
/// Complex numbers (real, image * i)
pub struct Complex {
pub real: i32,
pub imaginary: i32,
}使用结构字段中的速记
如果您不将derive_more用于new()，而不是指定field: field，只需指定field：
pub fn new(real: i32, imaginary: i32) -> Complex {
Complex { real, imaginary }
}不指定RHS的
类型
它默认为与实现类型相同的类型，因此不需要指定它。
impl ops::Mul for Complex { ... }最终代码
包含derive_more在内的所有更改的代码：
mod my_math {
use std::fmt;
#[derive(
Debug,
Clone,
Copy,
PartialEq,
Eq,
Default,
derive_more::Constructor,
derive_more::Add,
derive_more::Sub,
)]
/// Complex numbers (real, image * i)
pub struct Complex {
pub real: i32,
pub imaginary: i32,
}
impl fmt::Display for Complex {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "({}, {}i)", self.real, self.imaginary)
}
}
impl ops::Mul for Complex {
type Output = Complex;
fn mul(self, rhs: Complex) -> Self::Output {
Complex {
real: self.real * rhs.real - self.imaginary * rhs.imaginary,
imaginary: self.real * rhs.imaginary + self.imaginary * rhs.real,
}
}
}
}
fn main() {
let c0 = my_math::Complex::default();
assert_eq!(c0.real, 0);
assert_eq!(c0.imaginary, 0);
let c1 = my_math::Complex {
real: 1,
imaginary: 10,
};
let c2 = my_math::Complex::new(2, 20);
let c3 = c1 + c2;
let c3_expected = my_math::Complex::new(3, 30);
assert_eq!(c3, c3_expected);
println!("{}", c3);
}不包括derive_more的所有更改的代码：
mod my_math {
use std::fmt;
use std::ops;
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
/// Complex numbers (real, image * i)
pub struct Complex {
pub real: i32,
pub imaginary: i32,
}
impl Complex {
pub fn new(real: i32, imaginary: i32) -> Complex {
Complex { real, imaginary }
}
}
impl fmt::Display for Complex {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "({}, {}i)", self.real, self.imaginary)
}
}
impl ops::Add for Complex {
type Output = Complex;
fn add(self, rhs: Complex) -> Complex {
Complex {
real: rhs.real + self.real,
imaginary: rhs.imaginary + self.imaginary,
}
}
}
impl ops::Sub for Complex {
type Output = Complex;
fn sub(self, rhs: Complex) -> Complex {
Complex {
real: self.real - rhs.real,
imaginary: self.imaginary - rhs.imaginary,
}
}
}
impl ops::Mul for Complex {
type Output = Complex;
fn mul(self, rhs: Complex) -> Self::Output {
Complex {
real: self.real * rhs.real - self.imaginary * rhs.imaginary,
imaginary: self.real * rhs.imaginary + self.imaginary * rhs.real,
}
}
}
}
fn main() {
let c0 = my_math::Complex::default();
assert_eq!(c0.real, 0);
assert_eq!(c0.imaginary, 0);
let c1 = my_math::Complex {
real: 1,
imaginary: 10,
};
let c2 = my_math::Complex::new(2, 20);
let c3 = c1 + c2;
let c3_expected = my_math::Complex::new(3, 30);
assert_eq!(c3, c3_expected);
println!("{}", c3);
}
```#qcStackCode#页面原文内容由Code Review提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://codereview.stackexchange.com/questions/284886
复制相关文章
相似问题
腾讯云开发者
