Organizational standards and guidelines should be consulted before the reader continues this practice. The intrinsic data type bool is used, which has literal values true and false. Most compilers implement this correctly, but some do not. Data member names and class-scoped enumerations end with a single underscore. It is assumed that the file extensions .cpp and .hpp are appropriate.
Some compilers use a different convention.
In other words, each example demonstrates one basic point or technique, is as short as possible, and, if possible, is a complete, working program. Uncalled functions are often left undefined. Some functions that are called are also undefined, since compactness is a higher priority than self-contained functionality. This makes it easier for those who simply want to use the class as opposed to those who want to go in and change the internal implementation of the class. This is normally the right tradeoff since a class is normally used a lot more often than it is changed.