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一、Generic structures泛型结构体

泛型是一种编程语言的特性，它允许在代码中使用参数化类型，以便在不同地方使用
相同的代码逻辑处理多种数据类型，而无需为每种类型编写单独的代码！

作用：
1．提高代码的重用性
2．提高代码的可读性
3．提高代码的抽象度

1.泛型的应用类型

1．泛型定义结构体\枚举
2．泛型定义函数
3．泛型与特质

#[derive(Debug)]
struct Point<T> {x: T,y: T,
}#[derive(Debug)]
struct PointTwo<T, E> {x: T,y: E,
}
fn main() {let c1 = Point { x: 1.0, y: 2.0 };let c2 = Point { x: 'x', y: 'y' };println!("c1 {:?} c2 {:?}", c1, c2);let c = PointTwo { x: 1.0, y: 'z' };println!("{:?}", c);// Zero-Cost Abstraction
}

编译及运行：

 cargo runCompiling ch1_generic_struct v0.1.0 (/home/wangji/installer/rust/project/ch23_generic_struct)
warning: fields `x` and `y` are never read--> src/main.rs:3:5|
2 | struct Point<T> {|        ----- fields in this struct
3 |     x: T,|     ^
4 |     y: T,|     ^|= note: `Point` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis= note: `#[warn(dead_code)]` on by defaultwarning: fields `x` and `y` are never read--> src/main.rs:9:5|
8  | struct PointTwo<T, E> {|        -------- fields in this struct
9  |     x: T,|     ^
10 |     y: E,|     ^|= note: `PointTwo` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysiswarning: `ch1_generic_struct` (bin "ch1_generic_struct") generated 2 warningsFinished `dev` profile [unoptimized + debuginfo] target(s) in 0.30sRunning `target/debug/ch1_generic_struct`
c1 Point { x: 1.0, y: 2.0 } c2 Point { x: 'x', y: 'y' }
PointTwo { x: 1.0, y: 'z' }

二、Generic Function泛型函数

在Rust中，泛型也可以用于函数，使得函数能够处理多种类型的参数，提高代码的重用性和灵活性

1．泛型与普通函数
2．泛型与结构体中的方法

// 交换
fn swap<T>(a: T, b: T) -> (T, T) {(b, a)
}struct Point<T> {x: T,y: T,
}impl<T> Point<T> {// 构造函数fn new(x: T, y: T) -> Self {Point { x, y }}// 方法fn get_coordinates(&self) -> (&T, &T) {(&self.x, &self.y)}
}fn main() {let result = swap::<f64>(0.1, 1.0);let result: (f64, f64) = swap(0.1, 1.0);println!("{:?}", result);let str2 = swap("hh", "tt");println!("str2.0 {} str2.1 {}", str2.0, str2.1);let str2 = swap(str2.0, str2.1);println!("str2.0 {} str2.1 {}", str2.0, str2.1);let i32_point = Point::new(2, 3);let f64_point = Point::new(2.0, 3.0);let (x1, y1) = i32_point.get_coordinates();let (x2, y2) = f64_point.get_coordinates();println!("i32 point: x= {} y= {}", x1, y1);println!("f64 point: x= {} y= {}", x2, y2);// String 不要用&str//最好使用：let string_point = Point::new("xxx".to_owned(), "yyyy".to_owned());let string_point = Point::new("xxx", "yyyy");println!("string point x = {} y = {}", string_point.x, string_point.y);
}

编译及运行

 cargo runCompiling ch24_func v0.1.0 (/home/wangji/installer/rust/project/ch24_func)
warning: unused variable: `result`--> src/main.rs:23:9|
23 |     let result = swap::<f64>(0.1, 1.0);|         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`|= note: `#[warn(unused_variables)]` on by defaultwarning: `ch24_func` (bin "ch24_func") generated 1 warningFinished `dev` profile [unoptimized + debuginfo] target(s) in 0.33sRunning `target/debug/ch24_func`
(1.0, 0.1)
str2.0 tt str2.1 hh
str2.0 hh str2.1 tt
i32 point: x= 2 y= 3
f64 point: x= 2 y= 3
string point x = xxx y = yyyy

参考

• 2024 Rust现代实用教程