There are small MFC classes CPoint, CSize, and CRect holding a point (x and y), a size (width and height), and a rectangle (the four corners of). These classes will be thoroughly used in the following chapters.

We build our own classes Color and Font based upon the Win32 API types COLORREF and LOGFONT.

In every application, except Tetris, we display text. In order for the user to know where to enter the next character, we need a caret (a blinking vertical bar). The class Caret handles that.

The classes List and Set inherit the MFC class CList to handle list and sets, respectively. The Set class supports the mathematical operations union, intersection, and difference.

In the application of this book, two kinds of errors may occur: internalerrors, such as an index out of bounds, or a user errors, such as entering an incorrect formula. In the former case, we use the check macro to stop the execution with an error message; in the latter case, we throw an error exception that eventually...