FizzBuzz (the classic exercise)

This lesson covers solving FizzBuzz in R, with the aim of combining branching and looping.

FizzBuzz is the classic programming exercise. Print the numbers from 1 upwards, but print "Fizz" for multiples of 3, "Buzz" for multiples of 5, and "FizzBuzz" for multiples of both. It is perfect practice for branching.

The sample code loops from 1 to 15 and checks i %% 15 == 0 first so that multiples of 15 take priority, then multiples of 3 and 5. %% is R's remainder operator.

A common early stumble is the order of the checks. Test 3 and 5 first and a multiple of 15 prints just "Fizz", so the strictest condition has to come first.

Simple as it looks, getting the order wrong breaks it — which is why it turns up so often in interviews and training as a check on the fundamentals.

📖 Reference code

for (i in 1:15) {
  if (i %% 15 == 0) {
    cat("FizzBuzz\n")
  } else if (i %% 3 == 0) {
    cat("Fizz\n")
  } else if (i %% 5 == 0) {
    cat("Buzz\n")
  } else {
    cat(i, "\n")
  }
}

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run R directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).