C++ How to Program, 10/e

9.5 Access Functions and Utility Functions

Access Functions

Access functions can read or display data, not modify it. Another common use of access functions is to test the truth or falsity of conditions—such functions are often called predicate functions. An example would be an empty function for any container class—a class capable of holding many objects, such as an array or a vector. A program might test empty before attempting to read another item from the container object.2

2. Many programmers prefer to begin the names of predicate functions with the word “is.” For example, useful predicate functions for our Time class might be isAM and isPM.

Utility Functions

A utility function (also called a helper function) is a private member function ...