rust6.控制流

fn main() {
  let y = 1;
  //if
  if y == 1 {
    println!("y = 1 ");
  }

  //if - else 
  if y == 1 {
    println!("y == {}",y);
  }
  else {
    println!("y != 1");
  }
  // if -else if - else
  if y == 1 {println! ("y = 1");}
  else if y == 2 {
    println!("y = 2");
  }
  else if y == 3 {
    println!("y = 3 ");
  }
  else {
    println!("other!")
  }

  //let 中使用if
  //两个分支中的值应当属于同一类型
  let condition = true ;
  let x = if condition {
    5
  } else {
    6
  };
  println!("x = {} ",x);

  //loop
  let mut counter = 0;
  loop {
      println!("in loop");
      if counter == 10 {
          break;
        }
      counter += 1;
    }
  //let 和 loop
  let result = loop {
      counter += 1;
      if counter == 20 {
          break counter*2;
        }
    };
  //while 循环
  let mut i = 0;
  while i != 10 {
      i+= 1;
    }
  println!("i = {}",i);

  //for 循环
  let arr : [u32;5] = [1,2,3,4,5];
  //这种方法也可以
  //for element in &arr
  for element in arr.iter() {
      println!("element = {}",*element);
      //也可以使用
      //println!("element = {}",element);
    }
}