Rust笔记(四) 控制流

if 表达式

let number = 3;
if number < 5 {
    println!("less five")
} else if number > 5 && number < 10 {
    println!("more five, less ten")
} else {
    println!("more ten")
}

// 因为是表达式可以赋值
let result = if true {
    3
} else {
    5
};

loop 表达式

let mut count = 3;
let result = loop {
    if count == 5 {
        break count;
    }
    count += 1;
};

while 循环

while 循环内不能使用break关键字

let mut number = 3;
while number > 0 {
    number -= 1
}

for 循环

// for in
let arr = [1, 2, 3, 4, 5];
for element in arr.iter() {
    println!("t1 the value is: {}", element);
}

// for range
// (0...arr.len()) 只能正着，反转需要rev()
for i in (0..arr.len()) {
    println!("t2 the value is: {}", arr[i]);
}
//(0..a.len()).rev() 反转
for i in (0..arr.len()).rev() {
    println!("t3 the value is: {}", arr[i]);
}