课后4.md

语句和表达式

语句

1. 🌟🌟

// 使用两种方法让代码工作起来
fn main() {
   let v = {
       let mut x = 1;
       x += 2
       x
   };

   assert_eq!(v, 3);
}

fn main() {
   let v = {
       let mut x = 1;
       x += 2;
   };

   assert_eq!(v, ());
}

2. 🌟🌟

fn main1() {
   let v = {
        let x = 3;
        x
   }

   assert!(v == 3);
}

3. 🌟

fn main() {
    let s = sum(1 , 2);
    assert_eq!(s, 3);
}

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