We have learned a lot in this section about how to break problems down into these reusable named pieces of code called functions. In this section, we've learned the basic syntax of functions, including the return types, identifiers, and parameters, and how to write both the function prototypes, which go before the main function and the function definitions, which go after the main function. We learned about parameter passing schemes in which we control the type of access a function has to its parameters. By passing the parameter by value or by reference, we've also looked at function overloading, in which multiple functions can have the same name, but varied by their parameter lists. We also looked at recursion in which a function can call itself. We had some great projects in this section, including several simple regular projects and a more advanced project in which we implemented a simple game, Tic-Tac-Toe. This project really helped establish our strengths and weaknesses and showed us what a more involved nontrivial project looks like. In the next section, we will begin learning more about Object-Oriented Programming, one of the most popular and impressive features of C++. I'll see you in the next section.