重构主函数，添加泛型和特征实现，增加 Point 结构体及其方法，添加 Post 和 Weibo 结构体及其摘要功能，新增输出文件

main.rs

@@ -1,58 +1,162 @@
-struct Car {
-    color: String,
-    transmission: Transmission,
-    convertible: bool,
-    age: (Age, u32),
+use std::fmt::Display;
+
+fn add<T: std::ops::Add<Output = T>>(a: T, b: T) -> T {
+    a + b
 }
 
-#[derive(PartialEq, Debug)]
-enum Age {
-    New,
-    Used,
+fn largest<T: PartialOrd + Copy>(list: &[T]) -> T {
+    let mut largest = list[0];
+
+    for &item in list.iter() {
+        if item > largest {
+            largest = item;
+        }
+    }
+
+    largest
 }
 
-#[derive(PartialEq, Debug)]
-enum Transmission {
-    Manual,
-    SemiAuto,
-    Automatic,
+fn create_and_print<T>()
+where
+    T: From<i32> + Display,
+{
+    let a: T = 100.into();
+    println!("{}", a);
 }
 
-fn car_factory(color: String, transmission: Transmission, convertible: bool, miles: u32) -> Car {
-    Car {
-        color,
-        transmission,
-        convertible,
-        age: car_quality(miles),
+struct Point<T, U> {
+    x: T,
+    y: U,
+}
+
+impl<T, U> Point<T, U> {
+    fn mixup<V, W>(self, other: Point<V, W>) -> Point<T, W> {
+        Point {
+            x: self.x,
+            y: other.y,
+        }
     }
 }
 
-fn car_quality(miles: u32) -> (Age, u32) {
-    if miles > 100 {
-        return (Age::Used, miles);
+impl Point<i32, f64> {
+    fn distance_from_origin(&self) -> f64 {
+        ((self.x.pow(2) + (self.y as i32).pow(2)) as f64).sqrt()
     }
+}
 
-    (Age::New, miles)
+// fn display_array(arr: &[i32]) {
+//     println!("{:?}", arr);
+// }
+// fn display_array<T: std::fmt::Debug>(arr: &[T]) {
+//     println!("{:?}", arr);
+// }
+fn display_array<T: std::fmt::Debug, const N: usize>(arr: &[T; N]) {
+    println!("{:?}", arr);
+}
+
+struct Buffer<const N: usize> {
+    data: [u8; N],
+}
+
+const fn compute_buffer_size(factor: usize) -> usize {
+    1024 * factor
+}
+
+pub trait Summary {
+    fn summarize(&self) -> String;
+}
+
+pub struct Post {
+    pub title: String,
+    pub author: String,
+    pub content: String,
+}
+
+impl Summary for Post {
+    fn summarize(&self) -> String {
+        format!("{} by {}", self.title, self.author)
+    }
+}
+
+pub struct Weibo {
+    pub username: String,
+    pub content: String,
+    pub created_at: String,
+}
+
+impl Summary for Weibo {
+    fn summarize(&self) -> String {
+        format!("{}: {}", self.username, self.content)
+    }
+}
+
+pub fn notify(item: &impl Summary) {
+    println!("Breaking news! {}", item.summarize());
+}
+
+pub fn notify_plus<T: Summary>(item: &T, item2: &T) {
+    println!("Breaking news! {}", item.summarize());
+    println!("Breaking news! {}", item2.summarize());
 }
 
 fn main() {
-    println!("Hello, world");
-    let colors = ["Blue", "Green", "Red", "Silver"];
-    let mut car = car_factory(String::from(colors[0]), Transmission::Automatic, false, 0);
-    println!(
-        "Car order 1: {:?}, Hard top = {}, {:?}, {}, {} miles",
-        car.age.0, car.color, car.convertible, car.color, car.age.1
-    );
+    // let a = 1;
+    // let b = 1;
+    let a = 1.2;
+    let b = 1.4;
+    println!("{}", add(a, b));
+    create_and_print::<i64>();
 
-    car = car_factory(String::from(colors[1]), Transmission::SemiAuto, false, 1);
-    println!(
-        "Car order 1: {:?}, Hard top = {}, {:?},{:?}, {}, {} miles",
-        car.age.0, car.color, car.convertible, car.transmission, car.color, car.age.1
-    );
+    let p1 = Point { x: 5, y: 10.4 };
+    let p2 = Point { x: "Hello", y: 'c' };
 
-    car = car_factory(String::from(colors[2]), Transmission::Manual, false, 101);
-    println!(
-        "Car order 1: {:?}, Hard top = {}, {:?}, {}, {} miles",
-        car.age.0, car.color, car.convertible, car.color, car.age.1
-    );
+    let p3 = p1.mixup(p2);
+    println!("p3.x = {}, p3.y = {}", p3.x, p3.y);
+
+    let p4 = Point { x: 5, y: 10.4 };
+    println!("{}", p4.distance_from_origin());
+
+    let arr = [1, 2, 3, 4, 5];
+    display_array(&arr);
+
+    let arr: [i32; 3] = [1, 2, 3];
+    display_array(&arr);
+
+    const SIZE: usize = compute_buffer_size(10);
+    let buffer = Buffer { data: [0; SIZE] };
+    println!("{:?}", buffer.data.len());
+
+    let post = Post {
+        title: String::from("Post Title"),
+        author: String::from("Post Author"),
+        content: String::from("Post Content"),
+    };
+    println!("{}", post.summarize());
+
+    let weibo = Weibo {
+        username: String::from("Weibo User"),
+        content: String::from("Weibo Content"),
+        created_at: String::from("2021-01-01"),
+    };
+    println!("{}", weibo.summarize());
+    notify(&post);
+    notify(&weibo);
+
+    let post2 = Post {
+        title: String::from("Post Title 2"),
+        author: String::from("Post Author 2"),
+        content: String::from("Post Content 2"),
+    };
+    // notify_plus(&post, &weibo);
+    notify_plus(&post, &post2);
+
+    let number_list = vec![34, 50, 25, 100, 65];
+
+    let result = largest(&number_list);
+    println!("The largest number is {}", result);
+
+    let char_list = vec!['y', 'm', 'a', 'q'];
+
+    let result = largest(&char_list);
+    println!("The largest char is {}", result);
 }

minigrep/output.txt

@@ -0,0 +1,5 @@
+Searching for to
+In file poem.txt
+Case sensitive
+Are you nobody, too?
+How dreary to be somebody!