Rust 中的函数

函数的定义

• rust 中通过fn 关键字来定义函数

fn main() {
    say_hello();
}

fn say_hello() {
    println!("Hello, world!");
}

• 带有参数的函数

fn main() {
    let name = String::from("Zhang san");
    say_hello(&name);
}

fn say_hello(s: &String) {
    println!("Hello {}!", s);
}

//> Hello Zhang san!

函数的返回值

通过return 关键字返回

fn main() {
    let a = 123;
    let b = 456;
    let c = add_int(a, b);
    println!("c = {}", c);
}

fn add_int(x: i32, y: i32) -> i32 {
    return x + y;
}

//> c = 579

通过最后执行的表达式来返回（末尾不能有; 号）

fn main() {
    let a = 123;
    let b = 456;
    let c = add_int(a, b);
    println!("c = {}", c);
}

fn add_int(x: i32, y: i32) -> i32 {
    x + y
}

//> c = 579