# 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!
