rust控制流-各种循环

rust提供了3种循环，loop、while  和 for循环
loop反复直到喊停

fn main() {
    let mut _counter = 0;
    let result = loop {
        _counter += 1;
        if _counter == 10 {
            break _counter * 20;
        }
    };
    println!("result = {}", result);
}

　　二、while  当循环，每次执行循环体之前都判断一次条件。

fn main() {
    let mut _aaab = 0;
    while _aaab < 10 {
        _aaab += 1;
    }
    println!("_aaab = {}", _aaab);
}

　　倒计时

fn main() {
    let mut _aaab = 10;
    while _aaab != 0 {
        println!("_aaab = {}", _aaab);
        _aaab -= 1;
    }
}

　　三、for遍历循环

fn main() {
    let _a = [12, 231, 23, 34, 45, 56, 67, 78, 89, 90];
    for _s in _a.iter() {
        println!("{}", _s);
    }
}

　　四、Range（序列）和rev（反转）
标准库提供

fn main() {
    for num in (1..4).rev() {
        println!("{}", num);
    }
}