【Rust】配列【アルゴリズム】

fn main() {

   let mut a;
   let raikyaku: [i32; 7] = [521, 195, 221, 329, 352, 399, 450];

   let mut x = String::new();
   std::io::stdin().read_line(&mut x).expect("Failed to read line");
   let y  = x.trim_end().to_owned();
   a = y.parse::<usize>().unwrap();
   while a != 9 {
      if (a < 0 || a > 6) {
         println!("error");
      } else {
         println!("{}人", raikyaku[a]);
      }
      let mut x = String::new();
      std::io::stdin().read_line(&mut x).expect("Failed to read line");
      x = x.trim_end().to_owned();
      a = x.parse::<usize>().unwrap();
   }
}

fn main() {

   let raikyaku: [i32; 7] = [521, 195, 221, 329, 352, 399, 450];
   let (mut t, mut i) = (0, 0);

   while i < 7 {
      t = t + raikyaku[i];
      i += 1;
   }

   let av = t / i as i32;
   println!("合計: {}", t);
   println!("平均: {}", av);
}

合計: 2467
平均: 352