Getting started with functions

What exactly are C++ functions? A function is a collection of variables, expressions, and control flow statements (loops and branches). In fact, any of the code we have learned about in this book so far can be used in a function. The first part of a function that we write is called the signature. Here is an example function signature:

void shootLazers(int power, int direction);

If we add an opening and closing pair of curly braces {...} along with some code that the function performs, we will have a complete function, that is, a definition:

void shootLazers(int power, int direction)
{
    // ZAPP!
}

We could then use our new function from another part of our code, perhaps like this:

// Attack the player
shootLazers(50, 180) // Run the code in the function
// I'm back again - code continues here after the function ends

When we use a function, we say that we call it. At the point where we call shootLazers, our...