When a C or C++ executable program is
created, certain items are secretly linked in. One of these is the startup
module, which contains initialization routines that must
be run any time a C or C++ program begins to execute. These routines set up the
stack and initialize certain variables in the program.
The linker always searches the standard
library for the compiled versions of any
“standard” functions called in the program. Because the standard
library is always searched, you can use anything in that library by simply
including the appropriate header file in your program; you don’t have to
tell it to search the standard library. The iostream functions, for example, are
in the Standard C++ library. To use them, you just include the
<iostream> header file.
