C++ How to Program, 10/e

E.2 #include Preprocessing Directive

The #include preprocessing directive has been used throughout this text. The #include directive causes a copy of a specified file to be included in place of the directive. The two forms of the #include directive are

#include <filename>
#include "filename"

The difference between these is the location the preprocessor searches for the file to be included. If the filename is enclosed in angle brackets (< and >)—used for standard library header files—the preprocessor searches for the specified file in an implementation-dependent manner, normally through predesignated directories. If the file name is enclosed in quotes, the preprocessor searches first in the same directory as the file being compiled, then in ...