# FizzBuzz In this chapter we build the classic tech interview question: FizzBuzz. The idea is simple. Write a program that enumerates the integers from 0 to some stopping value, perhaps 100. For each integer: * If it is a multiple of 3, print Fizz * If it is a multiple of 5, print Buzz * If it is a multiple of both 3 *and* 5, print FizzBuzz * Otherwise, if none of the above applies, print the integer. The interviewer's hope is that you get twisted in knots trying to navigate the case where the integer is a multiple of both 3 and 5. There are many ways to solve this challenge. One way might be to test for being a multiple of 15 *first* and print FizzBuzz if true. Then test against 3 and then against 5. Another way is to accumulate the correct out by testing against 3 and adding Fizz to a buffer. Then test against 5 and if appropriate append Buzz to the buffer. Either the buffer was empty, in which case you get Buzz alone - or it already contained Fizz in which case the buffer now contains FizzBuzz. Finally, if *anything* is in the buffer, cause the buffer to be printed and append a new line. In C++, the buffer could be a C++ string or a stringstream. In C you might think that you must resort to using an array of `char` to act as the buffer, filling it with `strncpy` or some such nonsense. But you don't have to bother! `printf` is a buffered output stream. It won't print anything until it encounters a new line character. In this program, we'll use this to buffer up either Fizz, Buzz or both then as indicated above, we'll end with a new line and BAM - whatever was in the `printf` buffer gets sent to the console. [Here is a video](https://youtu.be/aJSGTIxu4ik) where we walk through the process of writing FizzBuzz from scratch in ARM 64 bit assembly language. [Here is the source code](./fizzbuzz.s). The video is long but there is much benefit to be had by watching and listening to another person's process as they write the code. **AND especially** listening and watching to them debug when things go wrong!