元组 §

长度固定，元素顺序固定

fn main() {
    let tup: (i32, f64, u8) = (500, 6.4, 1);
    // 解构赋值
    let (x, y, z) = tup;
    
    assert_eq!(x, tup.0);
    assert_eq!(y, tup.1);
    assert_eq!(z, tup.2);
}

元组作为函数返回值：

fn calculate_length(s: String) -> (String, usize) {
    let length = s.len();
    (s, length)
}