Day 05 - 迴圈(Loop) & While 迴圈(While Loop)

15th鐵人賽 rust 從0開始了解rust let's go rusty rust programming language

monles_yen

2023-09-08 16:17:10

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也有英文版文章
Also this tutorial has been written in English
Check out my Medium

⭐Rust的中文翻譯以參考這份檔案為主.

迴圈(Loop)

語法如下

fn main() {
    loop {
        println!("再一次！");
    }
}

$ cargo run
   Compiling loops v0.1.0 (file:///projects/loops)
    Finished dev [unoptimized + debuginfo] target(s) in 0.29s
     Running `target/debug/loops`
再一次！
再一次！
再一次！
再一次！
^C再一次！

🔹Example 01 - Loop

fn main() {
    let mut n = 1;
    loop {
        println!("{:?}", n);
        if n == 4 {
            break;
        }
        n = n + 1;
    }
}

/* 
Output
1
2
3
4
*/

🔹Example 02 - While Loop

fn main() {
    let mut counter = 5;
    while counter >= 1 {
        println!("{:?}", counter);
        counter = counter - 1;
    }
    println!("done!");
}

/* 
Output
5
4
3
2
1
done!
*/

或者換個寫法

fn main() {
    let mut counter = 5;
    let mut done = false;
    while !done {
        if counter > 0 {
            println!("{:?}", counter);
            counter = counter - 1;
        } else {
            done = true;
        }
    }
    println!("done!");
}