A data structure that uses encapsulation to hide its implementation, allowing programmers using the type to think abstractly about what the type does rather than concretely about how the type is represented. Classes in C++ can be used to define abstract data types.
access label
A public or private label that defines whether the following members are accessible to users of the class or only to the friends and members of the class. Each label sets the access protection for the members declared up to the next label. Labels may appear multiple times within the class.
class
C++ mechanism for defining our own abstract data types. Classes may have data, function or type members. A class defines a new type and a new scope.
class declaration
A class may be declared before it is defined. A class declaration is the keyword class (or struct) followed by the class name followed by a semicolon. A class that is declared but not defined is an incomplete type.
class keyword
In a class defined following the class keyword, the initial implicit access label is private.
class scope
Each class defines a scope. Class scopes are more complicated than other scopesmember functions defined within the class body may use names that appear after the definition.
concrete class
A class that exposes its implementation.
const member function
A member function that may not change an object's ordinary (i.e., neither static nor mutable) data members. The this pointer in a const member is a pointer to const. A member function may be overloaded based on whether the function is const.
constructor initializer list
Specifies initial values of the data members of a class. The members are initialized to the values specified in the initializer list before the body of the constructor executes. Class members that are not initialized in the initializer list are implicitly initialized by using their default constructor.
conversion constructor
A nonexplicit constructor that can be called with a single argument. A conversion constructor is used implicitly to convert from the argument's type to the class type.
data abstraction
Programming technique that focuses on the interface to a type. Data abstraction allows programmers to ignore the details of how a type is represented and to think instead about the operations that the type can perform. Data abstraction is fundamental to both object-oriented and generic programming.
default constructor
The constructor that is used when no initializer is specified.
encapsulation
Separation of implementation from interface; encapsulation hides the implementation details of a type. In C++, encapsulation is enforced by preventing general user access to the private parts of a class.
explicit constructor
Constructor that can be called with a single argument but that may not be used to perform an implicit conversion. A constructor is made explicit by prepending the keyword explicit to its declaration.
forward declaration
Declaration of an as yet undefined name. Most often used to refer to the declaration of a class that appears prior to the definition of that class. See incomplete type.
friend
Mechanism by which a class grants access to its nonpublic members. Both classes and functions may be named as friends. friends have the same access rights as members.
incomplete type
A type that has been declared but not yet defined. It is not possible use an incomplete type to define a variable or class member. It is legal to define references or pointers to incomplete types.
member function
Class member that is a function. Ordinary member functions are bound to an object of the class type through the implicit this pointer. Static member functions are not bound to an object and have no this pointer. Member functions may be overloaded, provided that the versions of the function are distinguished by number or type of their parameters.
mutable data member
Data member that is never const, even when it is a member of a const object. A mutable member can be changed inside a const function.
name lookup
The process by which the use of a name is matched to its corresponding declaration.
private members
Members defined after a private access label; accessible only to the friends and other class members. Data members and utility functions used by the class that are not part of the type's interface are usually declared private.
public members
Members defined after a public access label; public members are accessible to any user of the class. Ordinarily, only the functions that define the interface to the class should be defined in the public sections.
static member
Data or function member that is not a part of any object but is shared by all objects of a given class.
struct keyword
In a class defined following the struct keyword, the initial implicit access label is public.
synthesized default constructor
The default constructor created (synthesized) by the compiler for classes that do not define any constructors. This constructor initializes members of class type by running that class's default constructor; members of built-in type are uninitialized.
