FizzBuzz

A Roc solution to the popular FizzBuzz interview problem:

Print the integers from 1 to 100, replacing multiples of three with "Fizz", multiples of five with "Buzz", and multiples of both three and five with "FizzBuzz".

Code

app [main] { pf: platform "https://github.com/roc-lang/basic-cli/releases/download/0.16.0/O00IPk-Krg_diNS2dVWlI0ZQP794Vctxzv0ha96mK0E.tar.br" }

import pf.Stdout

main =
    List.range { start: At 1, end: At 100 }
    |> List.map fizzBuzz
    |> Str.joinWith ","
    |> Stdout.line

## Determine the FizzBuzz value for a given integer.
## Returns "Fizz" for multiples of 3, "Buzz" for
## multiples of 5, "FizzBuzz" for multiples of both
## 3 and 5, and the original number for anything else.
fizzBuzz : I32 -> Str
fizzBuzz = \n ->
    fizz = n % 3 == 0
    buzz = n % 5 == 0

    if fizz && buzz then
        "FizzBuzz"
    else if fizz then
        "Fizz"
    else if buzz then
        "Buzz"
    else
        Num.toStr n

## Test Case 1: not a multiple of 3 or 5
expect fizzBuzz 1 == "1"
expect fizzBuzz 7 == "7"

## Test Case 2: multiple of 3
expect fizzBuzz 3 == "Fizz"
expect fizzBuzz 9 == "Fizz"

## Test Case 3: multiple of 5
expect fizzBuzz 5 == "Buzz"
expect fizzBuzz 20 == "Buzz"

## Test Case 4: multiple of both 3 and 5
expect fizzBuzz 15 == "FizzBuzz"
expect fizzBuzz 45 == "FizzBuzz"

Output

Run this from the directory that has main.roc in it:

$ roc main.roc
1,2,Fizz,4,Buzz,Fizz,7,8,Fizz,Buzz,11,Fizz,13,14,FizzBuzz,16,17,Fizz,19,Buzz,Fizz,22,23,Fizz,Buzz,26,Fizz,28,29,FizzBuzz,31,32,Fizz,34,Buzz,Fizz,37,38,Fizz,Buzz,41,Fizz,43,44,FizzBuzz,46,47,Fizz,49,Buzz,Fizz,52,53,Fizz,Buzz,56,Fizz,58,59,FizzBuzz,61,62,Fizz,64,Buzz,Fizz,67,68,Fizz,Buzz,71,Fizz,73,74,FizzBuzz,76,77,Fizz,79,Buzz,Fizz,82,83,Fizz,Buzz,86,Fizz,88,89,FizzBuzz,91,92,Fizz,94,Buzz,Fizz,97,98,Fizz,Buzz

You can also use roc test to run the tests.