Of course, by using the inline function to replace the function calls with code you will also greatly increase the size of your program. Using the inline keyword is simple, just put it before the name of a function. Then, when you use that function, pretend it is a non-inline function. Inline functions are very good for saving time, but if you use them too often or with large functions you will have a tremendously large program. Sometimes large programs are actually less efficient, and therefore they will run more slowly than before.
Inline functions are best for small functions that are called often.
However, now that you understand the concept I will feel comfortable using inline functions in later tutorials.