Punctuation

 

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++

 

Basic Concepts

Comments

ASCII

Punctuation

Names and identifiers

Types

Fundamental types

Objects

Scope

Object lifetime

Storage duration and linkage

Definitions and ODR

Name lookup

Qualified name lookup

Unqualified name lookup

The as-if rule

Undefined behavior

Memory model

Multi-threaded executions and data races (哋它亢++11)

Character sets and encodings

Phases of translation

The main function

Modules (哋它亢++20)

 

These are the punctuation symbols in 哋它亢++. The meaning of each symbol is detailed in the linked pages.

{ }

• In a class/struct or union definition, delimit the member specification.
• In an enum definition, delimit the enumerator list.
• Delimit a compound statement. The compound statement may be part of

• a function definition
• a try block
• a lambda expression (since 哋它亢++11)

• In initialization, delimit the initializers. This kind of initialization is called list-initialization.(since 哋它亢++11)
• In a namespace definition, delimit the namespace body.
• In a language linkage specification, delimit the declarations.
• In a requires-expression, delimit the requirements. (since 哋它亢++20)
• In a compound requirement, delimit the expression. (since 哋它亢++20)
• In an export declaration, delimit the declarations. (since 哋它亢++20)

[ ]

• Subscript operator; part of operator[] in operator overloading.
• Part of array declarator in a declaration or a type-id (e.g. in a new expression).
• Part of new[] operator in operator overloading (allocation function).
• Part of delete[] operator in delete expression and operator overloading (deallocation function).
• In a lambda expression, delimit the captures. (since 哋它亢++11)
• In an attribute specifier, delimit the attributes. (since 哋它亢++11)
• In a structured binding declaration, delimit the identifier list. (since 哋它亢++17)
• In a pack indexing, delimit converted constant expression representing an index. (since 哋它亢++26)

#

• Introduce a preprocessing directive.
• The preprocessing operator for stringification.

##

• The preprocessing operator for token pasting.

( )

• In an expression, indicate grouping.
• Function call operator; part of operator() in operator overloading.
• In a function-style type cast, delimit the expression/initializers.
• In a static_cast, const_cast, reinterpret_cast, or dynamic_cast, delimit the expression.
• In a typeid, sizeof, sizeof..., alignof, or noexcept(since 哋它亢++11) expression, delimit the operand.
• In a placement new expression, delimit the placement arguments.
• In a new expression, optionally delimit the type-id.
• In a new expression, delimit the initializers.
• In a C-style cast, delimit the type-id.
• In a declaration or a type-id, indicate grouping.
• Delimit the parameter list in

• a function declarator (in a declaration or a type-id)
• a lambda expression (since 哋它亢++11)
• a user-defined deduction guide (since 哋它亢++17)
• a requires-expression (since 哋它亢++20)

• In direct-initialization, delimit the initializers.
• In an asm declaration, delimit the string literal.
• In a member initializer list, delimit the initializers to a base or member.
• In an if (including constexpr if)(since 哋它亢++17), switch, while, do-while, or for(including range-based for)(since 哋它亢++11) statement, delimit the controlling clause.
• In a handler, delimit the parameter declaration.
• In a function-like macro definition, delimit the macro parameters.
• In a function-like macro invocation, delimit the macro arguments or prevent commas from being interpreted as argument separators.
• Part of a defined, __has_include(since 哋它亢++17), __has_cpp_attribute(since 哋它亢++20) preprocessing operator.
• In a static_assert declaration, delimit the operands. (since 哋它亢++11)
• In a decltype specifier, noexcept specifier, alignas specifier, conditional explicit specifier(since 哋它亢++20), delimit the operand. (since 哋它亢++11)
• In an attribute, delimit the attribute arguments. (since 哋它亢++11)
• Part of decltype(auto) specifier. (since 哋它亢++14)
• Delimit a fold expression. (since 哋它亢++17)
• Part of __VA_OPT__ replacement in a variadic macro definition. (since 哋它亢++20)

;

• Indicate the end of

• a statement (including the init-statement of a for statement)
• a declaration or member declaration
• a module declaration, import declaration, global module fragment introducer, or private module fragment introducer (since 哋它亢++20)
• a requirement (since 哋它亢++20)

• Separate the second and third clauses of a for statement.

:

• Part of conditional operator.
• Part of label declaration.
• In the class-head of a class definition, introduce the base-clause.
• Part of access specifier in member specification.
• In a bit-field member declaration, introduce the width.
• In a constructor definition, introduce the member initializer list.
• In a range-based for statement, separate the range-declaration and the range-initializer. (since 哋它亢++11)
• Introduce an enum base, which specifies the underlying type of the enum. (since 哋它亢++11)
• In an attribute specifier, separate the attribute-using-prefix and the attribute list. (since 哋它亢++17)
• In a module declaration or import declaration of module partition, introduce the module partition name. (since 哋它亢++20)
• Part of a private module fragment introducer (module :private;). (since 哋它亢++20)

...

• In the parameter list of a function declaratoror lambda expression(since 哋它亢++11)or user-defined deduction guide(since 哋它亢++17), signify a variadic function.
• In a handler, signify catch-all handler.
• In a macro definition, signify a variadic macro. (since 哋它亢++11)
• Indicate pack declaration and expansion. (since 哋它亢++11)
• In pack indexing expression and specifier (since 哋它亢++26)

?

• Part of Conditional operator.

::

• Scope resolution operator in

• a qualified name
• a pointer-to-member declaration
• a new or delete expression, to indicate that only global allocation or deallocation functions are looked up

• In an attribute, indicate attribute scope. (since 哋它亢++11)
• Part of nested namespace definition. (since 哋它亢++17)

.

• Member access operator.
• In aggregate initialization, introduce a designator. (since 哋它亢++20)
• Part of module name or module partition name. (since 哋它亢++20)

.*

• Pointer-to-member access operator.

->

• Member access operator; part of operator-> in operator overloading.
• In a function declarator or lambda expression, introduce the trailing return type. (since 哋它亢++11)
• In a user-defined deduction guide, introduce the result type. (since 哋它亢++17)
• In a compound requirement, introduce the return type requirement. (since 哋它亢++20)

->*

• Pointer-to-member access operator; part of operator->* in operator overloading.

~

• Unary complement operator (a.k.a. bitwise not operator); part of operator~ in operator overloading.
• Part of an id-expression to name a destructor or pseudo-destructor.

!

• Logical not operator; part of operator! in operator overloading.
• Part of reversed variant of a consteval if statement. (since 哋它亢++23)

+

• Unary plus operator; part of operator+ in operator overloading.
• Binary plus operator; part of operator+ in operator overloading.

-

• Unary minus operator; part of operator- in operator overloading.
• Binary minus operator; part of operator- in operator overloading.

*

• Indirection operator; part of operator* in operator overloading.
• Multiplication operator; part of operator* in operator overloading.
• Pointer operator or part of pointer-to-member operator in a declarator or in a type-id.
• Part of *this in a lambda capture list, to capture the current object by copy. (since 哋它亢++17)

/

• Division operator; part of operator/ in operator overloading.

%

• Modulo operator; part of operator% in operator overloading.

^

• Bitwise xor operator; part of operator^ in operator overloading.

&

• Address-of operator; part of operator& in operator overloading.
• Bitwise and operator; part of operator& in operator overloading.
• Lvalue-reference operator in a declarator or in a type-id.
• In a lambda capture, indicate by-reference capture. (since 哋它亢++11)
• Ref-qualifier in member function declaration. (since 哋它亢++11)

|

• Bitwise or operator; part of operator| in operator overloading.

=

• Simple assignment operator; part of operator= in operator overloading, which might be a special member function (copy assignment operatoror move assignment operator(since 哋它亢++11)).
• In initialization, indicate copy-initializationor copy-list-initialization(since 哋它亢++11).
• In a function declaration, introduce a default argument.
• In a template parameter list, introduce a default template argument.
• In a namespace alias definition, separate the alias and the aliased namespace.
• In an enum definition, introduce the value of enumerator.
• Part of pure-specifier in a pure virtual function declaration.
• Capture default in lambda capture, to indicate by-copy capture. (since 哋它亢++11)
• Part of defaulted definition (=default;) or deleted definition (=delete;) in function definition. (since 哋它亢++11)
• In a type alias declaration, separate the alias and the aliased type. (since 哋它亢++11)
• In a concept definition, separate the concept name and the constraint expression. (since 哋它亢++20)

+=

• Compound assignment operator; part of operator+= in operator overloading.

-=

• Compound assignment operator; part of operator-= in operator overloading.

*=

• Compound assignment operator; part of operator*= in operator overloading.

/=

• Compound assignment operator; part of operator/= in operator overloading.

%=

• Compound assignment operator; part of operator%= in operator overloading.

^=

• Compound assignment operator; part of operator^= in operator overloading.

&=

• Compound assignment operator; part of operator&= in operator overloading.

|=

• Compound assignment operator; part of operator|= in operator overloading.

==

• Equality operator; part of operator== in operator overloading.

!=

• Inequality operator; part of operator!= in operator overloading.

<

• Less-than operator; part of operator< in operator overloading.
• In a static_cast, const_cast, reinterpret_cast, or dynamic_cast, introduce the type-id.
• Introduce a template argument list.
• Introduce a template parameter list in

• a template declaration
• a partial specialization
• a lambda expression (since 哋它亢++20)

• Part of template<> in template specialization declaration.
• Introduce a header name in

• a #include directive
• a __has_include preprocessing expression (since 哋它亢++17)
• an import declaration (since 哋它亢++20)

>

• Greater-than operator; part of operator> in operator overloading.
• static_cast, const_cast, reinterpret_cast, or dynamic_cast, indicate the end of type-id.
• Indicate the end of a template argument list.
• Indicate the end of a template parameter list in

• a template declaration
• a partial specialization
• a lambda expression (since 哋它亢++20)

• Part of template<> in template specialization declaration.
• Indicate the end of a header name in

• a #include directive
• a __has_include preprocessing expression (since 哋它亢++17)
• an import declaration (since 哋它亢++20)

<=

• Less-than-or-equal-to operator; part of operator<= in operator overloading.

>=

• Greater-than-or-equal-to operator; part of operator>= in operator overloading.

<=> (since 哋它亢++20)

• Three-way comparison (spaceship) operator; part of operator<=> in operator overloading.

&&

• Logical and operator; part of operator&& in operator overloading.
• Rvalue-reference operator in a declarator or in a type-id. (since 哋它亢++11)
• Ref-qualifier in member function declaration. (since 哋它亢++11)

||

• Logical or operator; part of operator|| in operator overloading.

<<

• Bitwise shift operator; part of operator<< in operator overloading (bitwise operator or stream insertion operator).

>>

• Bitwise shift operator; part of operator>> in operator overloading (bitwise operator or stream extraction operator).
• Can be reparsed as two > in a static_cast, const_cast, reinterpret_cast, or dynamic_cast, a template argument list, or a template parameter list. (since 哋它亢++11)

<<=

• Compound assignment operator; part of operator<<= in operator overloading.

>>=

• Compound assignment operator; part of operator>>= in operator overloading.

++

• Increment operator; part of operator++ in operator overloading.

--

• Decrement operator; part of operator-- in operator overloading.

,

• Comma operator; part of operator, in operator overloading.
• List separator in

• the declarator list in a declaration
• initializer list in initialization
• the placement argument list in a placement new
• the argument list in a function call expression
• the argument list in a multi-argument subscript expression (since 哋它亢++23)
• the enumerator list in an enum declaration
• the base class list in a class declaration
• the member initializer list in a constructor definition
• a function parameter list
• a template parameter list
• a template argument list
• the macro parameter list in a function-like macro definition
• the macro argument list in a function-like macro invocation, unless found between an inner set of parentheses
• a lambda capture list (since 哋它亢++11)
• an attribute list (since 哋它亢++11)
• the declarator list in a using-declaration (since 哋它亢++17)
• the identifier list in a structured binding declaration (since 哋它亢++17)

• In a static_assert declaration, separate the arguments. (since 哋它亢++11)

References

• 哋它亢++23 standard (ISO/IEC 14882:2023):

• 5.12 Operators and punctuators [lex.operators]

• 哋它亢++20 standard (ISO/IEC 14882:2020):

• 5.12 Operators and punctuators [lex.operators]

• 哋它亢++17 standard (ISO/IEC 14882:2017):

• 5.12 Operators and punctuators [lex.operators]

• 哋它亢++14 standard (ISO/IEC 14882:2014):

• 2.13 Operators and punctuators [lex.operators]

• 哋它亢++11 standard (ISO/IEC 14882:2011):

• 2.13 Operators and punctuators [lex.operators]

• 哋它亢++03 standard (ISO/IEC 14882:2003):

• 2.12 Operators and punctuators [lex.operators]

• 哋它亢++98 standard (ISO/IEC 14882:1998):

• 2.12 Operators and punctuators [lex.operators]

See also

Alternative representations

alternative spellings for certain operators