【rCore OS 开源操作系统】Rust 练习题题解: Enums
摘要
rCore OS 开源操作系统训练营学习中的代码练习部分。
在此记录下自己学习过程中的产物，以便于日后更有"收获感"。
后续还会继续完成其他章节的练习题题解。
正文
enums1
题目
rust
// enums1.rs
//
// No hints this time! ;)
// I AM NOT DONE
#[derive(Debug)]
enum Message {
// TODO: define a few types of messages as used below
}
fn main() {
println!("{:?}", Message::Quit);
println!("{:?}", Message::Echo);
println!("{:?}", Message::Move);
println!("{:?}", Message::ChangeColor);
}题解
目测就是基本的枚举值语法。
甚至简单到题目中出现了 No hints this time! ;)，不会做那就有点汗颜了。
参考资料：https://doc.rust-lang.org/stable/book/ch06-01-defining-an-enum.html
rust
// enums1.rs
//
// No hints this time! ;)
#[derive(Debug)]
enum Message {
// TODO: define a few types of messages as used below
}
fn main() {
println!("{:?}", Message::Quit);
println!("{:?}", Message::Echo);
println!("{:?}", Message::Move);
println!("{:?}", Message::ChangeColor);
}enums2
这里的核心知识点是，枚举与数据类型关联。
题目
rust
// enums2.rs
//
// Execute `rustlings hint enums2` or use the `hint` watch subcommand for a
// hint.
// I AM NOT DONE
#[derive(Debug)]
enum Message {
// TODO: define the different variants used below
}
impl Message {
fn call(&self) {
println!("{:?}", self);
}
}
fn main() {
let messages = [
Message::Move { x: 10, y: 30 },
Message::Echo(String::from("hello world")),
Message::ChangeColor(200, 255, 255),
Message::Quit,
];
for message in &messages {
message.call();
}
}题解
题解与上面一样。
rust
// enums2.rs
//
// Execute `rustlings hint enums2` or use the `hint` watch subcommand for a
// hint.
#[derive(Debug)]
enum Message {
// TODO: define the different variants used below
Move { x: i32, y: i32 },
Echo(String),
ChangeColor(i32, i32, i32),
Quit,
}
impl Message {
fn call(&self) {
println!("{:?}", self);
}
}
fn main() {
let messages = [
Message::Move { x: 10, y: 30 },
Message::Echo(String::from("hello world")),
Message::ChangeColor(200, 255, 255),
Message::Quit,
];
for message in &messages {
message.call();
}
}enums3
题目
rust
// enums3.rs
//
// Address all the TODOs to make the tests pass!
//
// Execute `rustlings hint enums3` or use the `hint` watch subcommand for a
// hint.
// I AM NOT DONE
enum Message {
// TODO: implement the message variant types based on their usage below
}
struct Point {
x: u8,
y: u8,
}
struct State {
color: (u8, u8, u8),
position: Point,
quit: bool,
message: String
}
impl State {
fn change_color(&mut self, color: (u8, u8, u8)) {
self.color = color;
}
fn quit(&mut self) {
self.quit = true;
}
fn echo(&mut self, s: String) { self.message = s }
fn move_position(&mut self, p: Point) {
self.position = p;
}
fn process(&mut self, message: Message) {
// TODO: create a match expression to process the different message
// variants
// Remember: When passing a tuple as a function argument, you'll need
// extra parentheses: fn function((t, u, p, l, e))
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_match_message_call() {
let mut state = State {
quit: false,
position: Point { x: 0, y: 0 },
color: (0, 0, 0),
message: "hello world".to_string(),
};
state.process(Message::ChangeColor(255, 0, 255));
state.process(Message::Echo(String::from("hello world")));
state.process(Message::Move(Point { x: 10, y: 15 }));
state.process(Message::Quit);
assert_eq!(state.color, (255, 0, 255));
assert_eq!(state.position.x, 10);
assert_eq!(state.position.y, 15);
assert_eq!(state.quit, true);
assert_eq!(state.message, "hello world");
}
}题解
在要求会用枚举的基础上，结合了常常配合枚举一起使用的模式匹配。
rust
// enums3.rs
//
// Address all the TODOs to make the tests pass!
//
// Execute `rustlings hint enums3` or use the `hint` watch subcommand for a
// hint.
enum Message {
// TODO: implement the message variant types based on their usage below
ChangeColor(u8, u8, u8),
Echo(String),
Move(Point),
Quit,
}
struct Point {
x: u8,
y: u8,
}
struct State {
color: (u8, u8, u8),
position: Point,
quit: bool,
message: String,
}
impl State {
fn change_color(&mut self, color: (u8, u8, u8)) {
self.color = color;
}
fn quit(&mut self) {
self.quit = true;
}
fn echo(&mut self, s: String) {
self.message = s
}
fn move_position(&mut self, p: Point) {
self.position = p;
}
fn process(&mut self, message: Message) {
// TODO: create a match expression to process the different message
// variants
// Remember: When passing a tuple as a function argument, you'll need
// extra parentheses: fn function((t, u, p, l, e))
match message {
Message::ChangeColor(r, g, b) => self.change_color((r, g, b)),
Message::Echo(string) => self.echo(string),
Message::Move(point) => self.move_position(point),
Message::Quit => self.quit(),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_match_message_call() {
let mut state = State {
quit: false,
position: Point { x: 0, y: 0 },
color: (0, 0, 0),
message: "hello world".to_string(),
};
state.process(Message::ChangeColor(255, 0, 255));
state.process(Message::Echo(String::from("hello world")));
state.process(Message::Move(Point { x: 10, y: 15 }));
state.process(Message::Quit);
assert_eq!(state.color, (255, 0, 255));
assert_eq!(state.position.x, 10);
assert_eq!(state.position.y, 15);
assert_eq!(state.quit, true);
assert_eq!(state.message, "hello world");
}
}