buzz.rs

extern mod std;

fn is_three(num: int) -> bool {
  num % 3 == 0
}

#[test]
fn test_is_three_with_not_three() {
  if is_three(1) {
    fail ~"One is not three";
  }
}

#[test]
fn test_is_three_with_three() {
  if !is_three(3) {
    fail ~"Three should be three";
  }
}

fn is_five(num: int) -> bool {
  num % 5 == 0
}

#[test]
fn test_is_five_with_not_five() {
  if is_five(1) {
    fail ~"One is not five";
  }
}

#[test]
fn test_is_five_with_five() {
  if !is_five(5) {
    fail ~"Five should be five";
  }
}

fn is_fifteen(num: int) -> bool {
  num % 15 == 0
}

#[test]
fn test_is_fifteen_with_not_fifteen() {
  if is_fifteen(1) {
    fail ~"One is not fifteen";
  }
}

#[test]
fn test_is_fifteen_with_fifteen() {
  if !is_fifteen(15) {
    fail ~"Fifteen should be fifteen";
  }
}


fn main() {
  for int::range(0, 100) |num| {
    io::println(
      if is_fifteen(num) { ~"FizzBuzz" }
      else if is_three(num) { ~"Fizz" }
      else if is_five(num) { ~"Buzz" }
      else { int::str(num) }
    );
  }
}

fizz.rs

extern mod std;

fn is_three(num: int) -> bool {
  num % 3 == 0
}

#[test]
fn test_is_three_with_not_three() {
  if is_three(1) {
    fail ~"One is not three";
  }
}

#[test]
fn test_is_three_with_three() {
  if !is_three(3) {
    fail ~"Three should be three";
  }
}

fn is_five(num: int) -> bool {
  num % 5 == 0
}

#[test]
fn test_is_five_with_not_five() {
  if is_five(1) {
    fail ~"One is not five";
  }
}

#[test]
fn test_is_five_with_five() {
  if !is_five(5) {
    fail ~"Five should be five";
  }
}

fn is_fifteen(num: int) -> bool {
  num % 15 == 0
}

#[test]
fn test_is_fifteen_with_not_fifteen() {
  if is_fifteen(1) {
    fail ~"One is not fifteen";
  }
}

#[test]
fn test_is_fifteen_with_fifteen() {
  if !is_fifteen(15) {
    fail ~"Fifteen should be fifteen";
  }
}
  

fn main() {
  for int::range(0, 100) |num| {
    let answer = 
      if is_fifteen(num){
        ~"FizzBuzz"
      }
      else if is_three(num) {
        ~"Fizz"
      }
      else if is_five(num) {
        ~"Buzz"
      }
      else {
        int::str(num)
      };
    io::println(answer)
  }
}