C++ Primer, Fifth Edition

Relationships among the IO Types

Conceptually, neither the kind of device nor the character size affects the IO operations we want to perform. For example, we’d like to use >> to read data regardless of whether we’re reading a console window, a disk file, or a string. Similarly, we’d like to use that operator regardless of whether the characters we read fit in a char or require a wchar_t.

The library lets us ignore the differences among these different kinds of streams by using inheritance. As with templates (§ 3.3, p. 96), we can use classes related by inheritance without understanding the details of how inheritance works. We’ll cover how C++ supports inheritance in Chapter 15 and in § 18.3 (p. 802).

Briefly, inheritance lets us say that a particular ...