函数的三种类型

  • 有参数有返回值
  • 有参数无返回值
  • 无参数无返回值
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fn other_fun() {
    println!("This is a function");
  }

fn other_fun1 (a: i32, b: u32) {
    println!("a = {} , b = {}" , a,b);
  }

fn other_fun2 (a :i32 , b: i32 ) -> i32 {
    let result = a + b;
    //c语言常用这种写法返回，但是Rust使用下面的写法较多
    //return result;
    result//或者直接使用a+b也可以
  }

fn main() {
    other_fun();
    let a: i32 = -1;
    let b: u32 = 20;
    let c: i32 = 6;
    other_fun1(a,b);
    let r: i32 = other_fun2(a,c);
    println!("r = {} ",r );
  }