rust-by-practice/src/why-exercise.md

Rust By Practice

This book was designed for easily diving into Rust，and it's very easy to use: All you need to do is to make each exercise compile without ERRORS and Panics !

Features

• There are three parts in each chapter: examples, exercises and practices

• Covering nearly all aspects of Rust, such as async/await, threads, sync primitives, optimizing and stand libraries etc

• Solution for each exercise

• Difficulty from easy to super hard: easy 🌟 medium 🌟🌟 hard 🌟🌟🌟 super hard 🌟🌟🌟🌟

• Both English and Chinsese are supported

Part of our examples and exercises are borrowed from Rust By Example, thanks for the great works you have been doing!

Some of our exercises

🌟🌟🌟 Tuple struct looks similar to tuples, it has added meaning the struct name provides but has no named fields. It's useful when you want give the whole tuple a name, but don't care the fields's names.

// fix the error and fill the blanks
struct Color(i32, i32, i32);
struct Point(i32, i32, i32);
fn main() {
    let v = Point(___, ___, ___);
    check_color(v);
}   

fn check_color(p: Color) {
    let (x, _, _) = p;
    assert_eq!(x, 0);
    assert_eq!(p.1, 127);
    assert_eq!(___, 255);
 }

🌟🌟 Within the destructuring of a single variable, both by-move and by-reference pattern bindings can be used at the same time. Doing this will result in a partial move of the variable, which means that parts of the variable will be moved while other parts stay. In such a case, the parent variable cannot be used afterwards as a whole, however the parts that are only referenced (and not moved) can still be used.

// fix errors to make it work
#[derive(Debug)]
struct File {
    name: String,
    data: String,
}
fn main() {
    let f = File {
        name: String::from("readme.md"),
        data: "Rust By Practice".to_string()
    };

    let _name = f.name;

    // ONLY modify this line
    println!("{}, {}, {:?}",f.name, f.data, f);
} 

🌟🌟 A match guard is an additional if condition specified after the pattern in a match arm that must also match, along with the pattern matching, for that arm to be chosen.

// fill in the blank to make the code work, `split` MUST be used
fn main() {
    let num = Some(4);
    let split = 5;
    match num {
        Some(x) __ => assert!(x < split),
        Some(x) => assert!(x >= split),
        None => (),
    }
}