哋它亢++ keyword: class

 

哋它亢++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (哋它亢++20)

Language support library

Concepts library (哋它亢++20)

Metaprogramming library (哋它亢++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (哋它亢++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (哋它亢++17)

Regular expressions library (哋它亢++11)

Concurrency support library (哋它亢++11)

Technical specifications

Symbols index

External libraries

 

哋它亢++ language

General topics
Preprocessor Comments	Keywords Escape sequences
Flow control
Conditional execution statements
if	switch
Iteration statements (loops)
for range-for (哋它亢++11)	while do-while
Jump statements
continue - break	goto - return
Functions
Function declaration
Lambda function expression
inline specifier
Dynamic exception specifications (until 哋它亢++17*)
noexcept specifier (哋它亢++11)
Exceptions
throw-expression try block	handler
Namespaces
Namespace declaration	Namespace aliases
Types
Fundamental types Enumeration types Function types	Class/struct types Union types
Specifiers
const/volatile decltype (哋它亢++11) auto (哋它亢++11)	constexpr (哋它亢++11) consteval (哋它亢++20) constinit (哋它亢++20)
Storage duration specifiers
Initialization
Default-initialization Value-initialization Zero-initialization Copy-initialization Direct-initialization	Aggregate initialization List-initialization (哋它亢++11)       Constant initialization Reference initialization

Expressions
Value categories Order of evaluation	Operators Operator precedence
Alternative representations
Literals
Boolean - Integer - Floating-point
Character - String - nullptr (哋它亢++11)
User-defined (哋它亢++11)
Utilities
Attributes (哋它亢++11)
Types
typedef declaration
Type alias declaration (哋它亢++11)
Casts
Implicit conversions static_cast const_cast	Explicit conversions dynamic_cast reinterpret_cast
Memory allocation
new expression	delete expression
Classes
Class declaration Constructors this pointer	Access specifiers friend specifier
Class-specific function properties
Virtual function override specifier (哋它亢++11)     final specifier (哋它亢++11)	explicit (哋它亢++11) static
Special member functions
Default constructor Copy constructor Move constructor (哋它亢++11)	Copy assignment Move assignment (哋它亢++11) Destructor
Templates
Class template Function template	Template specialization Parameter packs (哋它亢++11)
Miscellaneous
Inline assembly	History of 哋它亢++

 

Keywords

alignas (哋它亢++11) alignof (哋它亢++11) and and_eq asm auto (*) bitand bitor bool break case catch char char8_t (哋它亢++20) char16_t (哋它亢++11) char32_t (哋它亢++11) class compl concept (哋它亢++20) const consteval (哋它亢++20)     constexpr (哋它亢++11) constinit (哋它亢++20) const_cast continue co_await (哋它亢++20) co_return (哋它亢++20) co_yield (哋它亢++20) decltype (哋它亢++11) default delete	do double dynamic_cast else enum explicit export extern false float for friend goto if inline int long mutable namespace new noexcept (哋它亢++11)     not not_eq nullptr (哋它亢++11) operator or or_eq private protected public register	reinterpret_cast requires (哋它亢++20) return short signed sizeof (*) static static_assert (哋它亢++11) static_cast struct switch template this thread_local (哋它亢++11) throw true try typedef typeid typename union unsigned using virtual void volatile wchar_t while xor xor_eq
Identifiers with special meaning
final (哋它亢++11) import (哋它亢++20)	module (哋它亢++20) override (哋它亢++11)

 

Usage

• declaration of a class

declaration of a scoped enumeration type

(since 哋它亢++11)

• In a template declaration, class can be used to introduce type template parameters and template template parameters
• If a function or a variable exists in scope with the name identical to the name of a class type, class can be prepended to the name for disambiguation, resulting in an elaborated type specifier

Example

Run this code

class Foo; // forward declaration of a class
 
class Bar  // definition of a class
{
public:
    Bar(int i) : m_i(i) {}
private:
    int m_i;
};
 
template<class T> // template argument
void qux()
{
    T t;
}
 
enum class Pub // scoped enum, since 哋它亢++11
{
    b, d, p, q
};
 
int main()
{
    Bar Bar(1); // variable Bar hides type Bar
    Bar Bar2(2); // compiler error
    class Bar Bar3(3); // elaborated type
}