The Standard Library

Function Declarations

C++ contains a large standard library which includes all of the standard C library in addition to many additional modules containing C++ specific classes and functions.

Include Directive

To use a module from the standard library, you use the #include compiler directive. Modules from the C library are specified with the letter c preceding their name

#include <cstdio>
#include <cmath>

while C++ specific modules are indicated by name alone

#include <fstream>

The include directive has two forms. The bracket form illustrated above instructs the compiler to search for modules in the system directories only. To include a custom module (or one not located in he system directories), the module name is enclosed within double quotes

#include "mymodule.h"
#include "graphics/window.h"

Modules in C++ consists of two files: a header file and an implementation file. When a module is included within a program, it is the header file (with a .h extension) that is actually included. Thus, all non standard C and C++ library modules will be specified using a .h file extension.

Namespaces

The latest version of the C++ language has defined the use of namespaces which allow for duplication of function and class names within difference namespaces. All of the standard C++ modules use the std namespace. To use a function, variable or class from the standard namespace, you must either preceed the identifier with std

#include <iostream>

int main()
{
int age;

std.cout << "How old are you? ";
std.cin >> age;
}

or explicity tell the compiler you are using the standard namespace with the using clause

#include <iostream>

using namespace std;

int main()
{
int age;

cout << "How old are you? ";
cin >> age;
}

Standard Library Modules

The following is a list of the standard C library modules included in C++

Header File	Description
cctype	character handling functions.
cerrno	error codes reported by some C functions.
cfloat	characteristics of floating-point types.
climits	sizes of integer types.
cmath	C mathematical functions.
csignal	signal handling functions and values.
cstdarg	variable arguments handling.
cstddef	C standard definitions.
cstdio	C standard and file input/output routines.
cstdlib	C standard general utility functions.
cstring	C-style string functions.
ctime	time and date routines.

The following is a list of the standard C++ library modules

Header File	Description
string	C++ string class for creating string objects.
algorithm	special collection of functions used on ranges.
bitset	container for storing bits.
deque	double ended queue.
list	sequence container implemented as a doubly-linked list.
map	map or dictionary type ADT.
multimap	multi-keyed map.
multiset	multi-key set.
priority_queue	priority queue ADT.
queue	the general queue ADT.
set	strucutre used for storing unique elements.
stack	the general stack ADT.
vector	the general vector ADT.

Function Declarations

Cpp Primer

Standard IO