his_way.rs

fn main() {
  for int::range(1, 101) |num| {
    let mut answer;
    if is_fifteen(num){
      answer = "FizzBuzz"; }
    else if is_three(num) {
      answer = "Fizz";
    }
    else if is_five(num) {
      answer = "Buzz"; }
    else {
      answer = "";
    };
    io::println(answer)
  }
}

my_way.rs

fn main() {
  for int::range(1,101) |num| {
    let mut fb = ~"";
    if is_three(num) {
      fb = str::append(fb, "Fizz");
    }
    if is_five(num) {
      fb = str::append(fb, "Buzz");
    }
    if fb != ~"" {
      io::println(fb);
    }
  }
}