带返回值的函数

  1. fn hello() -> i32 {
  2.     123
  3. }

rust会将最后一个 expression 当做函数的返回值return，当然也可以用 return 123; 但通常idiomatic way是隐式返回最后一个expression

loop

  1. fn main() {
  2.     let mut counter = 0;
  4.     let result = loop {
  5.         counter += 1;
  7.         if counter == 10 {
  8.             break counter * 2;
  9.         }
  10.     };
  12.     println!("the result is {}", result);
  13. }

for

  1. fn main() {
  2.     let a = vec![1,2,3,4,5];
  3.     for e in a.iter() {
  4.         println!("the value is: {}", e);
  5.     }
  6. }