FizzBuzz Implementation in Java

Question

Fairly new to learning interview questions and I saw this one and gave it a shot. I would very much appreciate some constructive criticism of how I went about it and what you would tell me if you were the interviewer and watched me implement it this way.

public class FizzBuzz {
  public static void main(String[] args) {
    // Go from 1 to 100
    for (int i = 1; i <= 100; i++) {
      String result = "";
      if (i % 3 == 0) { // If divisible by 3
        result += "Fizz";
      }
      if (i % 5 == 0) { // If divisible by 5
        result += "Buzz";
      }
      // If it was divisible by either 3 or 5 (or both), print Fizz, Buzz, or FizzBuzz accordingly.
      if (i % 3 == 0 || i % 5 == 0) {
        System.out.println(result);
      } else { // Or else just print the integer
        System.out.println(i);
      }
    }
  }

Answer 1

The point of FizzBuzz is to weed out obviously unqualified candidates, not to over-optimize the solution or to show off. Your code is a fine interview answer.

Make sure that your braces all match up. It would be more conventional to use 4 or 8 spaces per level of indentation.

My main suggestion — and this is an opinionated nitpick — is to tone down the comments, because comments that restate obvious code give the impression that you might be unfamiliar with the language. Experienced programmers never write // Go from 1 to 100 to explain for (int i = 1; i <= 100; i++). If you feel compelled to demonstrate your documentation skills, write some JavaDoc instead.

Answer 2

Quite perfect so far.

public class FizzBuzz {
  public static void main(String[] args) {
    // Go from 1 to 100
    for (int i = 1; i <= 100; i++) {
 1)   String result = "";
 2)   if (i % 3 == 0) { // If divisible by 3
        result += "Fizz";
      }
 2)   if (i % 5 == 0) { // If divisible by 5
        result += "Buzz";
      }
      // If it was divisible by either 3 or 5 (or both), print Fizz, Buzz, or FizzBuzz accordingly.
  2)  if (i % 3 == 0 || i % 5 == 0) {
        System.out.println(result);
      } else { // Or else just print the integer
        System.out.println(i);
      }
    }
  }

The only things I see:

In 1) the interviewer could ask if the code could be made faster. In this case, while += is perfectly fine, you could use concat or StringBuilder(). But for FizzBuzz I see it as unnecessary optimization.

In 2) you are testing the conditions twice. This is not so good because if the condition changes, you will likely forget to update the code on both sides.

Better simply test the String.

if (!result.isEmpty())

Cleaner way is to avoid negation and exchange the branches

if (result.isEmpty()) {  // Print integer
  ...
}
else {                   //Print Fizz Buzz
  ... 
}

or use booleans

String result = "";  
boolean isFizz = i % 3 == 0;  
boolean isBuzz = i % 5 == 0;

if (isFizz || isBuzz) {
...
}

The next step which is overkill for interview question (so your solution is preferable because you less likely to commit errors, but it may be asked if the interviewer wants to know if you can clean up the code) is e.g. replacing i with something more descriptive ("number" in this case, "index" if you use it for array access and "counter" if it is only used to count sth down) and replace 3 and 5 as magic numbers by descriptive constants.

Answer 3

The thing about FizzBuzz is that you can write simple and elegant code to solve the problem in almost any program language without going over the top.

This code below is simple and shows you understand hierarchy of if/elseif/else:

public class FizzBuzz {
  public static void main(String[] args) {
    for (int i = 1; i <= 100; i++) {
      if (i%3 == 0 && i%5 == 0)
        System.out.println("FizzBuzz"); 
      else if (i%5 == 0) 
        System.out.println("Buzz"); 
      else if (i%3 == 0) 
        System.out.println("Fizz"); 
      else 
        System.out.println(i);
    }
  }
}

Answer 4

Here it is my c++ implementation. It uses a recursive algorithm. Basically the last iteration create the vector then the result array is populated on every recursion with a push_back. It uses the "module 15", "module 5", module 3" in a ternary operator series.

vector<string> FizzBuzz::execute(int n) {

    if(n == 0)
        return vector<string>();

    auto push = n % 15 == 0 ? "fizzbuzz" :
                n % 3 == 0 ? "fizz" :
                n % 5 == 0 ? "buzz" :
                to_string(n);

    auto execution = execute(n-1);
    execution.push_back(push);
    return execution;
}

Answer 5

Since you want to improve, compare these:

var x = default

if a
    x += i
if b 
    x += j

if x != default
    func(x)

.

var x = default

if (a & b)
    x = k
else if a
    x = i
else if b 
    x = j

if x != default
    func(x)

.

if (a & b)
   func(k)
else if a
   func(i)
else if b 
   func(j)

First, the most important thing you'll notice is that there isn't much of a difference. Second, you'll notice that the one where the reader spends the least amount of time to understand the intent of the code is the last one.

I used pseudocode because this isn't specific to java.

Answer 6

The "FizzBuzz" Programm is a coding kata.

Coding Katas are very simple problems which are easy to solve. And their main aim is not to solve the problem (since it is quite easy) but to train problem solving approaches.

One of this problem solving approaches (and the origin of Coding Katas) is Test Driven Developement (TDD).

So When I was the interviewer and you would not start the Coding by writing a Test you were not my first choice... ;o)