You have created a project and you have a lot of source files. Now, each time you wish to compile you specify all the source files for compiling. Imagine, you make a small change. Now. you repeat the whole compilation process again. Very tedious, right? No worries :) Help is coming your way in the form of Makefiles.
Forgive me, if you already know this and are laughing at the fact I just came across this only now. For the others like me, makefiles are files which help you compile your projects with ease.And the best thing, incase of a small change in your code, only the file with the change is recompiled. Obviously, all this depends on how you write your makefiles. A brilliant tutorial is provided here. The make documentation can be found here.