View source for Operators in C and C++

{{short description|List of operators in C and C++}}
{{Use American English|date = March 2019}}
{{Use dmy dates|date=December 2019}}
This is a list of [[operator (programming)|operator]]s in the [[C (programming language)|C]] and [[C++]] [[programming language]]s. 

All listed operators are in C++ and lacking indication otherwise, in C as well. Some tables include a "In C" column that indicates whether an operator is also in C. Note that C does not support [[operator overloading]].

When not overloaded, for the operators <code>&&</code>, <code>||</code>, and <code>,</code> (the [[comma operator]]), there is a [[sequence point]] after the evaluation of the first operand.

Most of the operators available in C and C++ are also available in other [[C-family]] languages such as [[C Sharp (programming language)|C#]], [[D (programming language)|D]], [[Java (programming language)|Java]], [[Perl]], and [[PHP]] with the same precedence, associativity, and semantics.

Many operators specified by a sequence of symbols are commonly referred to by a name that consists of the name of each symbol. For example, <code>+=</code> and <code>-=</code> are often called "plus equal(s)" and "minus equal(s)", instead of the more verbose "assignment by addition" and "assignment by subtraction".

==Operators==
In the following tables, lower case letters such as <code>a</code> and <code>b</code> represent literal values, object/variable names, or l-values, as appropriate. <code>R</code>, <code>S</code> and <code>T</code> stand for a data type, and <code>K</code> for a class or enumeration type. Some operators have alternative spellings using [[digraphs and trigraphs (programming)|digraphs and trigraphs]] or [[#Synonyms|operator synonyms]].

===Arithmetic===

C and C++ have the same arithmetic operators and all can be overloaded in C++.

{| class="wikitable" style="width:100%"
! colspan="2" rowspan="2" | Operation
! rowspan="2" | Syntax
! colspan="2" | C++ prototype
|-
! in class K
! outside class
|-
| {{rh}} colspan="2" | [[Addition]] 
| align="center" | {{nowrap| 1=<code>a '''+''' b</code>}}
| {{cpp|1=R K::operator +(S b);}}
| {{cpp|1=R operator +(K a, S b);}}
|-
| {{rh}} colspan="2" | [[Subtraction]]
| align="center" | <code>a '''-''' b</code>
| {{cpp|1=R K::operator -(S b);}}
| {{cpp|1=R operator -(K a, S b);}}
|- 
| {{rh}} colspan="2" | [[Unary operation|Unary]] plus; [[Type conversion#Type promotion|integer promotion]]
|align="center" | <code>'''+'''a</code> 
| {{cpp|1=R K::operator +();}}
| {{cpp|1=R operator +(K a);}}
|-
| {{rh}} colspan="2" | [[Unary operation|Unary]] minus; [[additive inverse]] 
| align="center" | <code>'''-'''a</code> 
| {{cpp|1=R K::operator -();}}
| {{cpp|1=R operator -(K a);}}
|-
| {{rh}} colspan="2" | [[Multiplication]]
| align="center" | <code>a '''*''' b</code> 
| {{cpp|1=R K::operator *(S b);}}
| {{cpp|1=R operator *(K a, S b);}}
|-
| {{rh}} colspan="2" | [[Division (mathematics)|Division]]
| align="center" | <code>a '''/''' b</code> 
| {{cpp|1=R K::operator /(S b);}}
| {{cpp|1=R operator /(K a, S b);}}
|-
| {{rh}} colspan="2" | [[Modulo operation|Modulo]]<ref name="modulo" group="lower-alpha" />
| align="center" | <code>a '''%''' b</code> 
| {{cpp|1=R K::operator %(S b);}}
| {{cpp|1=R operator %(K a, S b);}}
|-
| {{rh}} colspan="2" | Prefix [[Increment and decrement operators|increment]]
| align="center" | <code>'''++'''a</code>
| {{cpp|1=R& K::operator ++();}}
| {{cpp|1=R& operator ++(K& a);}}
|-
| {{rh}} colspan="2" | Postfix increment
| align="center" | <code>a'''++'''</code> 
| {{cpp|1=R K::operator ++(int);}}{{efn|name=dummy-int|The {{cpp|int}} is a dummy parameter to differentiate between prefix and postfix.}}
| {{cpp|1=R operator ++(K& a, int);}}{{efn|name=dummy-int}}
|-
| {{rh}} colspan="2" | Prefix [[Increment and decrement operators|decrement]]
| align="center" | <code>'''--'''a</code>
| {{cpp|1=R& K::operator --();}}
| {{cpp|1=R& operator --(K& a);}}
|-
| {{rh}} colspan="2" | Postfix decrement
| align="center" | <code>a'''--'''</code>
| {{cpp|1=R K::operator --(int);}}{{efn|name=dummy-int}}
| {{cpp|1=R operator --(K& a, int);}}{{efn|name=dummy-int}}
|}

===Relational===

All [[Relational operator|relational]] (comparison) operators can be overloaded in C++. Since [[C++20]], the inequality operator is automatically generated if <code>operator==</code> is defined and all four relational operators are automatically generated if <code>operator<=></code> is defined.<ref>{{cite web|url=https://en.cppreference.com/w/cpp/language/operators#Comparison_operators|title=Operator overloading§Comparison operators|website=cppreference.com}}</ref>

{| class="wikitable" style="width:100%"
! colspan="2" rowspan="2" | Operation 
! rowspan="2" | Syntax 
! rowspan="2" | In C
! colspan="2" | C++ prototype
|-
! in class K
! outside class
|-
| {{rh}} colspan="2" | Equal to 
| align="center" | <code>a '''==''' b</code>
| {{yes}}
| {{cpp|1=bool K::operator ==(S const& b) const;}}
| {{cpp|1=bool operator ==(K const& a, S const& b);}}
|-
| {{rh}} colspan="2" | Not equal to 
| style="text-align:center;" | <code>a '''!=''' b</code> || {{yes}}
| {{cpp|1=bool K::operator !=(S const& b) const;}}
| {{cpp|1=bool operator !=(K const& a, S const& b);}}
|- 
| {{rh}} colspan="2" | Greater than 
| style="text-align:center;" | <code>a '''>''' b</code> || {{yes}} 
| {{cpp|1=bool K::operator >(S const& b) const;}}
| {{cpp|1=bool operator >(K const& a, S const& b);}}
|-
| {{rh}} colspan="2" | Less than 
| style="text-align:center;" | <code>a '''<''' b</code> || {{yes}} 
| {{cpp|1=bool K::operator <(S const& b) const;}}
| {{cpp|1=bool operator <(K const& a, S const& b);}}
|-
| {{rh}} colspan="2" | Greater than or equal to 
| style="text-align:center;" | <code>a '''>=''' b</code> || {{yes}} 
| {{cpp|1=bool K::operator >=(S const& b) const;}}
| {{cpp|1=bool operator >=(K const& a, S const& b);}}
|-
| {{rh}} colspan="2" | Less than or equal to 
| style="text-align:center;" | <code>a '''<=''' b</code> || {{yes}}
| {{cpp|1=bool K::operator <=(S const& b) const;}}
| {{cpp|1=bool operator <=(K const& a, S const& b);}}
|-
| {{rh}} colspan="2" | [[Three-way comparison]]<ref name="threewaycomparison" group="lower-alpha"/>{{efn|Possible return types: <code>std::weak_ordering</code>, <code>std::strong_ordering</code> and <code>std::partial_ordering</code> to which they all are convertible to.}}
| style="text-align:center;" | <code>a '''&lt;=&gt;''' b</code> || {{no}}
| {{cpp|1=auto K::operator <=>(const S &b);}}
| {{cpp|1=auto operator <=>(const K &a, const S &b);}}
|}

===Logical===

C and C++ have the same logical operators and all can be overloaded in C++.

Note that overloading logical ''AND'' and ''OR'' is discouraged, because as overloaded operators they always evaluate both operands instead of providing the normal semantics of [[short-circuit evaluation]].<ref>{{Cite web|url=https://isocpp.org/wiki/faq/operator-overloading|title=Standard C++}}</ref>

{| class="wikitable" style="width:100%"
! colspan="2" rowspan="2" | Operation
! rowspan="2" | Syntax 
! colspan="2" | C++ prototype
|-
! in class K
! outside class
|- 
| {{rh}} colspan="2" | [[Negation|NOT]] 
| align="center" | <code>'''!'''a</code>
| {{cpp|1=bool K::operator !();}}
| {{cpp|1=bool operator !(K a);}}
|-
| {{rh}} colspan="2" | [[Logical conjunction|AND]] 
| style="text-align:center;" | <code>a '''&&''' b</code>
| {{cpp|1=bool K::operator &&(S b);}}
| {{cpp|1=bool operator &&(K a, S b);}}
|-
| {{rh}} colspan="2" | [[Logical disjunction|OR]] 
| style="text-align:center;" | <code>a '''<nowiki>||</nowiki>''' b</code>
| {{code|1=bool K::operator {{!!}}(S b);|lang=cpp}}
| {{code|1=bool operator {{!!}}(K a, S b);|lang=cpp}}
|}

===Bitwise===

C and C++ have the same bitwise operators and all can be overloaded in C++.

{| class="wikitable" style="width:100%"
! colspan="2" rowspan="2" | Operation
! rowspan="2" | Syntax 
! colspan="2" | C++ prototype
|-
! in class K
! outside class
|-
| {{rh}} colspan="2" | [[Bitwise operation#NOT|NOT]]
| align="center" | <code>'''~'''a</code><br/>
| {{cpp|1=R K::operator ~();}}
| {{cpp|1=R operator ~(K a);}}
|-
| {{rh}} colspan="2" | [[Bitwise operation#AND|AND]]
| style="text-align:center;" | <code>a '''&''' b</code>
| {{cpp|1=R K::operator &(S b);}}
| {{cpp|1=R operator &(K a, S b);}}
|-
| {{rh}} colspan="2" | [[Bitwise operation#OR|OR]]
| style="text-align:center;" | <code>a '''<nowiki>|</nowiki>''' b</code>
| {{cpp|1=R K::operator {{!}}(S b);|lang=cpp}}
| {{cpp|1=R operator {{!}}(K a, S b);|lang=cpp}}
|-
| {{rh}} colspan="2" | [[Bitwise operation#XOR|XOR]]
| style="text-align:center;" | <code>a '''^''' b</code>
| {{cpp|1=R K::operator ^(S b);}}
| {{cpp|1=R operator ^(K a, S b);}}
|- 
| {{rh}} colspan="2" | [[Bitwise shift|Shift]] left<ref name="bitshift" group="lower-alpha" />
| style="text-align:center;" | <code>a '''<<''' b</code> 
| {{cpp|1=R K::operator <<(S b);}}
| {{cpp|1=R operator <<(K a, S b);}}
|-
| {{rh}} colspan="2" | Shift right<ref name="bitshift" group="lower-alpha" />{{Refn | Operation="rightbitshift" | group="lower-alpha" | According to the C99 standard, the right shift of a negative number is implementation defined. Most implementations, e.g., the GCC,<ref name="Integers">{{Citation | contribution = Integers implementation | url = //gcc.gnu.org/onlinedocs/gcc-4.3.3/gcc/Integers-implementation.html#Integers-implementation | title = GCC 4.3.3 | publisher = GNU}}.</ref> use an [[arithmetic shift]] (i.e., sign extension), but a [[logical shift]] is possible.}}
| style="text-align:center;" | <code>a '''>>''' b</code> 
| {{cpp|1=R K::operator >>(S b);}}
| {{cpp|1=R operator >>(K a, S b);}}
|}

===Assignment===

C and C++ have the same assignment operators and all can be overloaded in C++.

For the combination operators, <code>a ⊚= b</code> (where <code>⊚</code> represents an operation) is equivalent to <code>a = a ⊚ b</code>, except that <code>a</code> is evaluated only once.

{| class="wikitable" style="width:100%"
! rowspan="2" | Operation
! rowspan="2" | Syntax 
! colspan="2" | C++ prototype
|-
! in class K
! outside class
|-
! {{rh}} | [[Assignment operator (C++)|Assignment]] 
| style="text-align:center;" | {{nowrap| 1=<code>a '''=''' b</code>}}
| {{cpp|1=R& K::operator =(S b);}}
| {{n/a}}
|-
! {{rh}} | Addition combination
| align="center" | <code>a '''+=''' b</code>
| {{cpp|1=R& K::operator +=(S b);}}
| {{cpp|1=R& operator +=(K& a, S b);}}
|-
! {{rh}} | Subtraction combination 
| style="text-align:center;" | <code>a '''-=''' b</code>
| {{cpp|1=R& K::operator -=(S b);}}
| {{cpp|1=R& operator -=(K& a, S b);}}
|-
! {{rh}} | Multiplication combination 
| style="text-align:center;" | <code>a '''*=''' b</code>
| {{cpp|1=R& K::operator *=(S b);}}
| {{cpp|1=R& operator *=(K& a, S b);}}
|-
! {{rh}} | Division combination
| style="text-align:center;" | <code>a '''/=''' b</code>
| {{cpp|1=R& K::operator /=(S b);}}
| {{cpp|1=R& operator /=(K& a, S b);}}
|-
! {{rh}} | Modulo combination 
| style="text-align:center;" | <code>a '''%=''' b</code> 
| {{cpp|1=R& K::operator %=(S b);}}
| {{cpp|1=R& operator %=(K& a, S b);}}
|-
! {{rh}} | Bitwise AND combination
| style="text-align:center;" | <code>a '''&=''' b</code>
| {{cpp|1=R& K::operator &=(S b);}}
| {{cpp|1=R& operator &=(K& a, S b);}}
|-
! {{rh}} | Bitwise OR combination 
| style="text-align:center;" | <code>a '''<nowiki>|</nowiki>=''' b</code>
| {{cpp|1=R& K::operator {{!}}=(S b);|lang=cpp}}
| {{cpp|1=R& operator {{!}}=(K& a, S b);|lang=cpp}}
|-
! {{rh}} | Bitwise XOR combination
| style="text-align:center;" | <code>a '''^=''' b</code>
| {{cpp|1=R& K::operator ^=(S b);}}
| {{cpp|1=R& operator ^=(K& a, S b);}}
|-
! {{rh}} | Bitwise left shift combination
| style="text-align:center;" | <code>a '''<<=''' b</code>
| {{cpp|1=R& K::operator <<=(S b);}}
| {{cpp|1=R& operator <<=(K& a, S b);}}
|-
! {{rh}} | Bitwise right shift combination{{Refn | name="rightbitshift" | group="lower-alpha" | According to the C99 standard, the right shift of a negative number is implementation defined. Most implementations, e.g., the GCC,<ref name="Integers">{{Citation | contribution = Integers implementation | url = //gcc.gnu.org/onlinedocs/gcc-4.3.3/gcc/Integers-implementation.html#Integers-implementation | title = GCC 4.3.3 | publisher = GNU}}.</ref> use an [[arithmetic shift]] (i.e., sign extension), but a [[logical shift]] is possible.}}
| style="text-align:center;" | <code>a '''>>=''' b</code>
| {{cpp|1=R& K::operator >>=(S b);}}
| {{cpp|1=R& operator >>=(K& a, S b);}}
|}

===Member and pointer===
{| class="wikitable" style="width:100%"
! colspan="2" rowspan="2" | Operation
! rowspan="2" | Syntax
! rowspan="2" | Can overload
! rowspan="2" | In C
! colspan="2" | C++ prototype
|-
! in class K
! outside class
|-
| {{rh}} colspan="2" | [[Indexer (programming)|Subscript]]
| align="center" | <code>a'''['''b''']'''</code><code>a'''<:'''b''':>'''</code><ref>{{Cite web |title=ISO/IEC 9899:1999 specification, TC3 |url=https://www.open-std.org/jtc1/sc22/WG14/www/docs/n1256.pdf#%5B%7B%22num%22%3A148%2C%22gen%22%3A0%7D%2C%7B%22name%22%3A%22XYZ%22%7D%2C-27%2C816%2Cnull%5D |at=p. 64, § 6.4.6 ''Ponctuators'' para. 3}}</ref>
| {{yes}}
| {{yes}}
| {{cpp|1=R& K::operator [](S b);}}<br/>{{cpp|1=R& K::operator [](S b, ...);}}<ref name="sinceCXX23" group="lower-alpha" />
| {{n/a}}
|-
| {{rh}} colspan="2" | Indirection <br>{{small|(object pointed to by ''a'')}}
| style="text-align:center;" | <code>'''*'''a</code> || {{yes}} || {{yes}} 
| {{cpp|1=R& K::operator *();}}
| {{cpp|1=R& operator *(K a);}}
|-
| {{rh}} colspan="2" | Address-of <br>{{small|(address of ''a'')}}
| style="text-align:center;" | <code>'''&'''a</code> || {{yes}}<ref name="addressof2" group="lower-alpha"/> || {{yes}} 
| {{cpp|1=R* K::operator &();}}
| {{cpp|1=R* operator &(K a);}}
|-
| {{rh}} colspan="2" | Structure dereference <br>{{small|(member ''b'' of object pointed to by ''a'')}}
| style="text-align:center;" | <code>a'''->'''b</code> || {{yes}} || {{yes}} 
| {{cpp|1=R* K::operator ->();}}<ref name="arrowptr" group="lower-alpha" /><br />
| {{n/a}}
|-
| {{rh}} colspan="2" | Structure reference <br>{{small|(member ''b'' of object ''a'')}}
| style="text-align:center;" | <code>a'''.'''b</code> || {{no}} || {{yes}} 
| {{rh}} colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | Member selected by [[pointer-to-member]] ''b'' of object pointed to by ''a''<ref name="arrowstar" group="lower-alpha" />
| style="text-align:center;" | <code>a'''->*'''b</code> || {{yes}} || {{no}} 
| {{cpp|1=R& K::operator ->*(S b);}}
| {{cpp|1=R& operator ->*(K a, S b);}}
|-
| {{rh}} colspan="2" | Member of object ''a'' selected by [[pointer-to-member]] ''b''
| style="text-align:center;" | <code>a'''.*'''b</code> || {{no}} || {{no}} 
| {{rh}} colspan="2" {{n/a}}
|}

===Other===
{| class="wikitable" style="width:100%"
! colspan="2" rowspan="2" | Operation
! rowspan="2" | Syntax
! rowspan="2" | Can overload
! rowspan="2" | In C
! colspan="2" | C++ prototype
|-
! in class K
! outside class
|- 
| {{rh}} colspan="2" | [[function (programming)|Function]] call
| align="center" | <code>a'''('''a1, a2''')'''</code>
| {{yes}}
| {{yes}}
| {{cpp|1=R K::operator ()(S a, T b, ...);}}<!--'operator' shows as blue even though other prototypes shows it as green; seems to be a bug in the cpp template; unknown how to workaround.-->
| {{n/a}}
|-
| {{rh}} colspan="2" | [[comma operator|Comma]] 
| style="text-align:center;" | <code>a''',''' b</code> || {{yes}} || {{yes}} 
| {{cpp|1=R K::operator ,(S b);}}
| {{cpp|1=R operator ,(K a, S b);}}
|-
| {{rh}} colspan="2" | [[?:|Ternary conditional]] 
| style="text-align:center;" | <code>a '''?''' b ''':''' c</code> || {{no}} || {{yes}} 
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | [[Scope resolution operator#C++|Scope resolution]] 
| style="text-align:center;" | <code>a'''::'''b</code><ref name="scopal" group="lower-alpha" /> || {{no}} || {{no}} 
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | User-defined literals<ref name="ud-literal" group="lower-alpha" /><ref name="sinceCXX11" group="lower-alpha" />
| style="text-align: center;" | <code><nowiki>"a"_b</nowiki></code> || {{yes}} || {{no}}
| {{n/a}}
| {{cpp|1=R operator "" _b(T a)}}
|-
| {{rh}} colspan="2" | [[Sizeof]]
| style="text-align:center;" | <code>'''sizeof''' a</code><ref name="sizeof" group="lower-alpha" /><br /><code>'''sizeof''' (R)</code> || {{no}} || {{yes}} 
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | Size of [[variadic template|parameter pack]]<ref name="sinceCXX11" group="lower-alpha" />
| style="text-align:center;" | <code>'''sizeof...'''(Args)</code> || {{no}} || {{no}}
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | Alignof<ref name="sinceCXX11" group="lower-alpha" />
| style="text-align:center;" | <code>'''alignof'''(R)</code> <br> or <code>'''_Alignof'''(R)</code><ref name="alignof" group="lower-alpha"/> || {{no}} || {{yes}} 
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | [[Decltype]]<ref name="sinceCXX11" group="lower-alpha" />
| style="text-align:center;" | <code>'''decltype''' (a)</code><br/><code>'''decltype''' (R)</code> || {{no}} || {{no}}
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | Type identification 
| style="text-align:center;" | <code>'''typeid'''(a)</code><br><code>'''typeid'''(R)</code> || {{no}} || {{no}} 
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | [[type conversion|Conversion]]<br>{{small|(C-style cast)}} 
| style="text-align:center;" | <code>(R)a</code> || {{yes}} || {{yes}}
| {{cpp|1=K::operator R();}}<ref>{{cite web|url=https://en.cppreference.com/w/cpp/language/cast_operator|title=user-defined conversion|access-date=5 April 2020}}</ref>
| {{n/a}}
|-
| {{rh}} colspan="2" | [[type conversion|Conversion]]{{efn|Behaves like const_cast/static_cast/reinterpret_cast. In the last two cases, the <code>auto</code> specifier is replaced with the type of the invented variable x declared with <code>auto x(a);</code> (which is never interpreted as a function declaration) or <code>auto x{a};</code>, respectively.}}<ref>[https://en.cppreference.com/w/cpp/language/explicit_cast Explicit type conversion] in C++</ref>
| style="text-align:center;" | <code>R(a)</code><br><code>R{a}</code><ref name="sinceCXX11" group="lower-alpha" /><br><code>auto(a)</code><ref name="sinceCXX23" group="lower-alpha" /><br><code>auto{a}</code><ref name="sinceCXX23" group="lower-alpha" /> || {{no}} || {{no}}
| {{rh}} colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | [[static_cast]] conversion{{efn|For user-defined conversions, the return type implicitly and necessarily matches the operator name unless the type is inferred (e.g. {{cpp|1=operator auto()}}, {{cpp|1=operator decltype(auto)()}} etc.).}}
| style="text-align:center;" | <code>'''static_cast'''<R>(a)</code> || {{yes}} || {{no}}
| {{cpp|1=K::operator R();}}<br>{{cpp|1=explicit K::operator R();}}<ref name="sinceCXX11" group="lower-alpha" />
| {{n/a}}
|-
| {{rh}} colspan="2" | [[dynamic cast]] conversion
| style="text-align:center;" | <code>'''dynamic_cast'''<R>(a)</code> || {{no}} || {{no}}
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | [[const_cast]] conversion
| style="text-align:center;" | <code>'''const_cast'''<R>(a)</code> || {{no}} || {{no}}
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | [[reinterpret_cast]] conversion
| style="text-align:center;" | <code>'''reinterpret_cast'''<R>(a)</code> || {{no}} || {{no}}
| colspan="2" {{n/a}}
|-
| {{rh}} colspan="2" | [[new (c++)|Allocate storage]] 
| style="text-align:center;" | <code>'''new''' R</code><ref name="infer" group="lower-alpha"/> || {{yes}} || {{no}} 
| {{cpp|1=void* K::operator new(size_t x);}}
| {{cpp|1=void* operator new(size_t x);}}
|-
| {{rh}} colspan="2" | Allocate array 
| style="text-align:center;" | <code>'''new''' R'''['''n''']'''</code><ref name="infer2" group="lower-alpha"/> || {{yes}} || {{no}} 
| {{cpp|1=void* K::operator new[](size_t a);}}
| {{cpp|1=void* operator new[](size_t a);}}
|-
| {{rh}} colspan="2" | [[operator delete|Deallocate storage]]
| style="text-align:center;" | <code>'''delete''' a</code> || {{yes}} || {{no}} 
| {{cpp|1=void K::operator delete(void* a);}}
| {{cpp|1=void operator delete(void* a);}}
|-
| {{rh}} colspan="2" | Deallocate array 
| style="text-align:center;" | <code>'''delete[]''' a</code> || {{yes}} || {{no}} 
| {{cpp|1=void K::operator delete[](void* a);}}
| {{cpp|1=void operator delete[](void* a);}}
|-
| {{rh}} colspan="2" | Exception check<ref name="sinceCXX11" group="lower-alpha" />
| style="text-align:center;" | <code>'''noexcept'''(a)</code> || {{no}} || {{no}}
| colspan="2" {{n/a}}
|}

=== Synonyms ===
C++ defines keywords to act as aliases for a number of operators:<ref name="Committee">{{cite book | title = ISO/IEC 14882:1998(E) Programming Language C++ | date = 1 September 1998 | publisher = open-std.org – The C++ Standards Committee | pages = 40–41}}</ref>
{| class="wikitable" style="width:30%; text-align:center;"
! Keyword || Operator
|-
| {{code|and}} || <code>&&</code>
|-
| {{code|and_eq}} || <code>&=</code>
|-
| {{code|bitand}} || <code>&</code>
|-
| {{code|bitor}} || <code>&#x7C;</code>
|-
| {{code|compl}} || <code>~</code>
|-
| {{code|not}} || <code>!</code>
|-
| {{code|not_eq}} || <code>!=</code>
|-
| {{code|or}} || <code>&#x7C;&#x7C;</code>
|-
| {{code|or_eq}} || <code>&#x7C;=</code>
|-
| {{code|xor}} || <code>^</code>
|-
| {{code|xor_eq}} || <code>^=</code>
|}

Each keyword is a different way to specify an operator and as such can be used instead of the corresponding symbolic variation. For example, {{code|1=(a > 0 and not flag)}} and {{code|1=(a > 0 && !flag)}} specify the same behavior. As another example, the <code>bitand</code> keyword may be used to replace not only the ''bitwise-and'' operator but also the ''address-of'' operator, and it can be used to specify reference types (e.g., {{code|1=int bitand ref = n}}). 

The ISO C specification makes allowance for these keywords as preprocessor macros in the header file [[iso646.h|{{code|iso646.h}}]]. For compatibility with C, C++ also provides the header {{code|iso646.h}}, the inclusion of which has no effect. Until C++20, it also provided the corresponding header [[ciso646|{{code|ciso646}}]] which had no effect as well.

==Expression evaluation order==
During expression evaluation, the order in which sub-expressions are evaluated is determined by [[order of operations|precedence]] and [[operator associativity|associativity]]. An operator with higher precedence is evaluated before a operator of lower precedence and the operands of an operator are evaluated based on associativity. The following table describes the precedence and associativity of the C and C++ operators. Operators are shown in groups of equal precedence with groups ordered in descending precedence from top to bottom (lower order is higher precedence).<ref>{{cite book | title = ISO/IEC 9899:201x Programming Languages - C | date = 19 December 2011 | publisher = open-std.org – The C Standards Committee | pages = 465}}</ref><ref>{{cite tech report |title=the ISO C 1999 standard, section 6.5.6 note 71 |institution=ISO |year=1999 }}</ref><ref>{{cite web |title=C++ Built-in Operators, Precedence and Associativity |url=https://docs.microsoft.com/en-US/cpp/cpp/cpp-built-in-operators-precedence-and-associativity |website=docs.microsoft.com |access-date=11 May 2020 |language=en-us}}</ref>

Operator precedence is not affected by overloading. 

{| class="wikitable"
|-
! style="text-align: left" | Order
! style="text-align: left" | Operator
! style="text-align: left" | Description
! style="text-align: left" | Associativity
|-
! 1
<small>highest</small>
| <code>::</code>
| [[Scope resolution operator#C.2B.2B|Scope resolution]] (C++ only)
| None
|-
! rowspan=11| 2
| style="border-bottom-style: none" | <code>++</code>
| style="border-bottom-style: none" | Postfix increment
| style="vertical-align: top" rowspan="11" | Left-to-right
|-
| style="border-bottom-style: none; border-top-style: none" | <code>--</code>
| style="border-bottom-style: none; border-top-style: none" | Postfix decrement
|-
| style="border-bottom-style: none; border-top-style: none" | <code>()</code>
| style="border-bottom-style: none; border-top-style: none" | Function call
|-
| style="border-bottom-style: none; border-top-style: none" | <code>[]</code>
| style="border-bottom-style: none; border-top-style: none" | Array subscripting
|-
| style="border-bottom-style: none; border-top-style: none" | <code>.</code>
| style="border-bottom-style: none; border-top-style: none" | Element selection by reference
|-
| style="border-bottom-style: none; border-top-style: none" | <code>-&gt;</code>
| style="border-bottom-style: none; border-top-style: none" | Element selection through pointer
|-
| style="border-bottom-style: none; border-top-style: none" | <code>typeid()</code>
| style="border-bottom-style: none; border-top-style: none" | [[Run-time type information]] (C++ only) (see [[typeid]])
|-
| style="border-bottom-style: none; border-top-style: none" | <code>const_cast</code>
| style="border-bottom-style: none; border-top-style: none" | Type cast (C++ only) (see [[const_cast]])
|-
| style="border-bottom-style: none; border-top-style: none" | <code>dynamic_cast</code>
| style="border-bottom-style: none; border-top-style: none" | Type cast (C++ only) (see [[dynamic cast]])
|-
| style="border-bottom-style: none; border-top-style: none" | <code>reinterpret_cast</code>
| style="border-bottom-style: none; border-top-style: none" | Type cast (C++ only) (see [[reinterpret_cast]])
|-
| style="border-top-style: none" | <code>static_cast</code>
| style="border-top-style: none" | Type cast (C++ only) (see [[static_cast]])
|-
! rowspan="13" | 3
| style="border-bottom-style: none" | <code>++</code>
| style="border-bottom-style: none" | Prefix increment
| rowspan="13" style="vertical-align: top" | Right-to-left
|-
| style="border-bottom-style: none; border-top-style: none" | <code>--</code>
| style="border-bottom-style: none; border-top-style: none" | Prefix decrement
|-
| style="border-bottom-style: none; border-top-style: none" | <code>+</code>
| style="border-bottom-style: none; border-top-style: none" | Unary plus
|-
| style="border-bottom-style: none; border-top-style: none" | <code>-</code>
| style="border-bottom-style: none; border-top-style: none" | Unary minus
|-
| style="border-bottom-style: none; border-top-style: none" | <code>!</code>
| style="border-bottom-style: none; border-top-style: none" | Logical NOT
|-
| style="border-bottom-style: none; border-top-style: none" | <code>~</code>
| style="border-bottom-style: none; border-top-style: none" | Bitwise NOT ([[ones' complement]])
|-
| style="border-bottom-style: none; border-top-style: none" | <code>(''type'')</code>
| style="border-bottom-style: none; border-top-style: none" | Type cast
|-
| style="border-bottom-style: none; border-top-style: none" | <code>*</code>
| style="border-bottom-style: none; border-top-style: none" | Indirection (dereference)
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&</code>
| style="border-bottom-style: none; border-top-style: none" | Address-of 
|-
| style="border-bottom-style: none; border-top-style: none" | <code>sizeof</code>
| style="border-bottom-style: none; border-top-style: none" | [[Sizeof]]
|-
| style="border-bottom-style: none; border-top-style: none" | <code>_Alignof</code>
| style="border-bottom-style: none; border-top-style: none" | Alignment requirement (since C11)
|-
| style="border-bottom-style: none; border-top-style: none" | <code>new</code>, <code>new[]</code>
| style="border-bottom-style: none; border-top-style: none" | Dynamic memory allocation (C++ only)
|-
| style="border-top-style: none" | <code>delete</code>, <code>delete[]</code>
| style="border-top-style: none" | Dynamic memory deallocation (C++ only)
|-
! rowspan=2| 4
| style="border-bottom-style: none" | <code>.*</code>
| style="border-bottom-style: none" | Pointer to member (C++ only)
| style="vertical-align: top" rowspan="2" | Left-to-right
|-
| style="border-bottom-style: none; border-top-style: none" | <code>->*</code>
| style="border-bottom-style: none; border-top-style: none" | Pointer to member (C++ only)
|-
! rowspan=3| 5
| style="border-bottom-style: none" | <code>*</code>
| style="border-bottom-style: none" | Multiplication
| style="vertical-align: top" rowspan="3" | Left-to-right
|-
| style="border-bottom-style: none; border-top-style: none" | <code>/</code>
| style="border-bottom-style: none; border-top-style: none" | Division
|-
| style="border-bottom-style: none; border-top-style: none" | <code>%</code>
| style="border-bottom-style: none; border-top-style: none" | [[Modulo operation|Modulo]] (remainder)
|-
! rowspan=2| 6
| style="border-bottom-style: none" | <code>+</code>
| style="border-bottom-style: none" | Addition
| style="vertical-align: top" rowspan="2" | Left-to-right
|-
| style="border-bottom-style: none; border-top-style: none" | <code>-</code>
| style="border-bottom-style: none; border-top-style: none" | Subtraction
|-
! rowspan=2| 7
| style="border-bottom-style: none" | <code>&lt;&lt;</code>
| style="border-bottom-style: none" | [[Bitwise operation|Bitwise]] left shift
| style="vertical-align: top" rowspan="2" | Left-to-right
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&gt;&gt;</code>
| style="border-bottom-style: none; border-top-style: none" | [[Bitwise operation|Bitwise]] right shift
|-
! rowspan=1| 8
| style="border-bottom-style:none;" | <code>&lt;=&gt;</code>
| style="border-bottom-style:none;" | [[Three-way comparison]] (Introduced in [[C++20]] - C++ only)
| style="vertical-align: top" rowspan="1" | Left-to-right
|-
! rowspan=4| 9
| style="border-bottom-style: none" | <code>&lt;</code>
| style="border-bottom-style: none" | Less than
| style="vertical-align: top" rowspan="4" | Left-to-right
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&lt;=</code>
| style="border-bottom-style: none; border-top-style: none" | Less than or equal to
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&gt;</code>
| style="border-bottom-style: none; border-top-style: none" | Greater than
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&gt;=</code>
| style="border-bottom-style: none; border-top-style: none" | Greater than or equal to
|-
! rowspan=2| 10
| style="border-bottom-style: none" | <code>==</code>
| style="border-bottom-style: none" | Equal to
| style="vertical-align: top" rowspan="2" | Left-to-right
|-
| style="border-bottom-style: none; border-top-style: none" | <code>!=</code>
| style="border-bottom-style: none; border-top-style: none" | Not equal to
|-
! 11
| <code>&</code>
| Bitwise AND
| Left-to-right
|-
! 12
| <code>^</code>
| Bitwise XOR (exclusive or)
| Left-to-right
|-
! 13
| <code><nowiki>|</nowiki></code>
| Bitwise OR (inclusive or)
| Left-to-right
|-
! 14
| <code>&&</code>
| Logical AND
| Left-to-right
|-
! 15
| <code><nowiki>||</nowiki></code>
| Logical OR
| Left-to-right
|-
! rowspan="2" | 16
| style="border-bottom-style: none" | <code>co_await</code>
| rowspan="2" | Coroutine processing (C++ only)
| rowspan="2" | Right-to-left
|-
| style="border-top-style: none" | <code>co_yield</code>
|-
! rowspan="13" | 17
| style="border-bottom-style: none" | <code>?:</code>
| style="border-bottom-style: none" | [[Ternary conditional operator]]
| rowspan="13" | Right-to-left
|-
| style="border-bottom-style: none; border-top-style: none" | <code>=</code>
| style="border-bottom-style: none; border-top-style: none" | Direct assignment
|-
| style="border-bottom-style: none; border-top-style: none" | <code>+=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by sum
|-
| style="border-bottom-style: none; border-top-style: none" | <code>-=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by difference
|-
| style="border-bottom-style: none; border-top-style: none" | <code>*=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by product
|-
| style="border-bottom-style: none; border-top-style: none" | <code>/=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by quotient
|-
| style="border-bottom-style: none; border-top-style: none" | <code>%=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by remainder
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&lt;&lt;=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by bitwise left shift
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&gt;&gt;=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by bitwise right shift
|-
| style="border-bottom-style: none; border-top-style: none" | <code>&=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by bitwise AND
|-
| style="border-bottom-style: none; border-top-style: none" | <code>^=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by bitwise XOR
|-
| style="border-bottom-style: none; border-top-style: none" | <code><nowiki>|</nowiki>=</code>
| style="border-bottom-style: none; border-top-style: none" | Assignment by bitwise OR
|-
| style="border-top-style: none" | <code>throw</code>
| style="border-top-style: none" | Throw operator (exceptions throwing, C++ only)
|-
! 18
<small>lowest</small>
| <code>,</code>
| [[Comma operator|Comma]]
| Left-to-right
|}

===Details===
Although this table is adequate for describing most evaluation order, it does not describe a few details. The [[ternary operator]] allows any arbitrary expression as its middle operand, despite being listed as having higher precedence than the assignment and comma operators. Thus <code>a ? b, c : d</code> is interpreted as <code>a ? (b, c) : d</code>, and not as the meaningless <code>(a ? b), (c : d)</code>. So, the expression in the middle of the conditional operator (between <code>'''?'''</code> and <code>''':'''</code>) is parsed as if parenthesized. Also, the immediate, un-parenthesized result of a C cast expression cannot be the operand of <code>sizeof</code>. Therefore, <code>sizeof (int) * x</code> is interpreted as <code>(sizeof(int)) * x</code> and not <code>sizeof ((int) * x)</code>.

===Chained expressions===
The precedence table determines the order of binding in chained expressions, when it is not expressly specified by parentheses.
* For example, <code>++x*3</code> is ambiguous without some precedence rule(s). The precedence table tells us that: {{mono|x}} is 'bound' more tightly to {{mono|++}} than to {{mono|*}}, so that whatever {{mono|++}} does (now or later—see below), it does it ONLY to {{mono|x}} (and not to <code>x*3</code>); it is equivalent to (<code>++x</code>, <code>x*3</code>).
* Similarly, with <code>3*x++</code>, where though the post-fix {{mono|++}} is designed to act AFTER the entire expression is evaluated, the precedence table makes it clear that ONLY {{mono|x}} gets incremented (and NOT <code>3*x</code>). In fact, the expression (<code>tmp=x++</code>, <code>3*tmp</code>) is evaluated with {{mono|tmp}} being a temporary value. It is functionally equivalent to something like (<code>tmp=3*x</code>, <code>++x</code>, <code>tmp</code>).
[[Image:Precedence 2.png|center|thumb|Precedence and bindings]]
* Abstracting the issue of precedence or binding, consider the diagram above for the expression 3+2*y[i]++. The compiler's job is to resolve the diagram into an expression, one in which several unary operators (call them 3+( . ), 2*( . ), ( . )++ and ( . )[ i ]) are competing to bind to y. The order of precedence table resolves the final sub-expression they each act upon: ( . )[ i ] acts only on y, ( . )++ acts only on y[i], 2*( . ) acts only on y[i]++ and 3+( . ) acts 'only' on 2*((y[i])++). It is important to note that WHAT sub-expression gets acted on by each operator is clear from the precedence table but WHEN each operator acts is not resolved by the precedence table; in this example, the ( . )++ operator acts only on y[i] by the precedence rules but binding levels alone do not indicate the timing of the postfix ++ (the ( . )++ operator acts only after y[i] is evaluated in the expression).

===Binding===
The binding of operators in C and C++ is specified by a factored language grammar, rather than a precedence table. This creates some subtle conflicts. For example, in C, the syntax for a conditional expression is:
<syntaxhighlight lang="c">logical-OR-expression ? expression : conditional-expression</syntaxhighlight>
while in C++ it is:
<syntaxhighlight lang="cpp">logical-OR-expression ? expression : assignment-expression</syntaxhighlight>
Hence, the expression:
<syntaxhighlight lang="text">e = a < d ? a++ : a = d</syntaxhighlight>
is parsed differently in the two languages. In C, this expression is a syntax error, because the syntax for an assignment expression in C is:
<syntaxhighlight lang="c">unary-expression '=' assignment-expression</syntaxhighlight>
In C++, it is parsed as:
<syntaxhighlight lang="cpp">e = (a < d ? a++ : (a = d))</syntaxhighlight>
which is a valid expression.<ref>{{cite web |title=C Operator Precedence - cppreference.com |url=https://en.cppreference.com/w/c/language/operator_precedence |website=en.cppreference.com |access-date=10 April 2020}}</ref><ref>{{Cite web|url=https://stackoverflow.com/questions/13515434/does-the-c-c-ternary-operator-actually-have-the-same-precedence-as-assignment/13515505|title=Does the C/C++ ternary operator actually have the same precedence as assignment operators?|website=Stack Overflow|access-date=2019-09-22}}</ref>

To use the comma operator in a function call argument expression, variable assignment, or a comma-separated list, use of parentheses is required.<ref>{{cite web |title=Other operators - cppreference.com |url=https://en.cppreference.com/w/c/language/operator_other |website=en.cppreference.com |access-date=10 April 2020}}</ref><ref>{{cite web |title=c++ - How does the Comma Operator work |url=https://stackoverflow.com/questions/54142/how-does-the-comma-operator-work/ |website=Stack Overflow |access-date=1 April 2020}}</ref> For example, 

<syntaxhighlight lang="cpp">
int a = 1, b = 2, weirdVariable = (++a, b), d = 4;
</syntaxhighlight>

===Criticism of bitwise and equality operators precedence===
The precedence of the bitwise logical operators has been criticized.<ref name="Bell">{{Citation | url = https://www.bell-labs.com/usr/dmr/www/chist.html | title = C history § Neonatal C| publisher = Bell labs}}.</ref> Conceptually, & and | are arithmetic operators like * and +.

The expression {{cpp|1=a & b == 7}} is syntactically parsed as {{cpp|1=a & (b == 7)}} whereas the expression {{cpp |1=a + b == 7}} is parsed as {{cpp|1=(a + b) == 7}}. This requires parentheses to be used more often than they otherwise would.

Historically, there was no syntactic distinction between the bitwise and logical operators. In [[BCPL]], [[B (programming language)|B]] and early C, the operators {{cpp|&& {{!!}}}} didn't exist. Instead {{cpp|& {{!}}}} had different meaning depending on whether they are used in a 'truth-value context' (i.e. when a Boolean value was expected, for example in {{cpp|1= if (a==b & c) {...} }} it behaved as a logical operator, but in {{cpp|1= c = a & b}} it behaved as a bitwise one). It was retained so as to keep [[backward compatibility]] with existing installations.<ref>{{cite web|url=https://www.perlmonks.org/?node_id=1159769|title=Re^10: next unless condition|website=www.perlmonks.org|access-date=23 March 2018}}</ref>

Moreover, in C++ (and later versions of C) equality operations, with the exception of the three-way comparison operator, yield [[Boolean data type|bool]] type values which are conceptually a single bit (1 or 0) and as such do not properly belong in "bitwise" operations.

==Notes==
{{reflist |group="lower-alpha"|refs=
<ref name="sinceCXX11" group="lower-alpha">since C++11</ref>
<ref name="sinceCXX23" group="lower-alpha">since C++23</ref>
<ref name="modulo" group="lower-alpha">The modulus operator only supports integer operands; for floating point, a function such as [[math.h|{{code|fmod|cpp}}]] can be used.</ref>
<ref name="bitshift" group="lower-alpha">In the context of [[iostream]]s in C++, writers often will refer to {{cpp|<<}} and {{cpp|>>}} as the "put-to" or "stream insertion" and "get-from" or "stream extraction" operators, respectively.</ref>
<ref name="addressof2" group="lower-alpha">The actual address of an object with an overloaded <code>operator &</code> can be obtained with [https://en.cppreference.com/w/cpp/memory/addressof <code>std::addressof</code>]</ref>
<ref name="arrowptr" group="lower-alpha">The return type of {{cpp|operator->()}} must be a type for which the {{cpp |->}} operation can be applied, such as a pointer type. If {{cpp|x}} is of type {{cpp |C}} where {{cpp |C}} overloads {{cpp|operator->()}}, {{cpp|x->y}} gets expanded to {{cpp|x.operator->()->y}}.</ref>
<ref name="arrowstar" group= "lower-alpha">{{Citation | publisher = Aristeia | url = http://aristeia.com/Papers/DDJ_Oct_1999.pdf | title = Implementing operator-&gt;* for Smart Pointers | first = Scott | last = Meyers | journal = Dr. Dobb's Journal |date=Oct 1999}}.</ref>
<ref name="scopal" group="lower-alpha">Although a <code>::</code> punctuator exists in C as of C23, it is not used as a scope resolution operator.</ref>
<ref name="ud-literal" group="lower-alpha">About [http://en.cppreference.com/w/cpp/language/user_literal C++11 User-defined literals]</ref>
<ref name="sizeof" group="lower-alpha">The parentheses are not necessary when taking the size of a value, only when taking the size of a type. However, they are usually used regardless.{{Citation needed|date=July 2024}}</ref>
<ref name="alignof" group = "lower-alpha">C++ defines <code>alignof</code> operator, whereas C defines <code>_Alignof</code> (C23 defines both). Both operators have the same semantics.</ref>
<ref name="threewaycomparison" group="lower-alpha">About [https://en.cppreference.com/w/cpp/language/operator_comparison#Three-way_comparison C++20 three-way comparison]</ref>

<ref name="infer" group="lower-alpha">The type name can also be inferred (e.g <code>new auto</code>) if an initializer is provided.</ref>
<ref name="infer2" group="lower-alpha">The array size can also be inferred if an initializer is provided.</ref>
}}

==See also==
* {{Annotated link|Bitwise operations in C}}
* {{Annotated link|Bit manipulation}}
* {{Annotated link|Logical operator}}
* {{Annotated link|Boolean algebra (logic)}}
* {{Annotated link|Table of logic symbols}}

== References ==
{{Reflist|30em}}

==External links==
* {{Citation | url = https://en.cppreference.com/w/cpp/language/expressions#Operators | contribution = Operators | title = C++ reference | type = wiki}}.
*[https://en.cppreference.com/w/c/language/operator_precedence C Operator Precedence]
* {{Citation | url = https://docs.microsoft.com/en-US/cpp/cpp/postfix-increment-and-decrement-operators-increment-and-decrement | title = Postfix Increment and Decrement Operators: ++ and -- | date = 17 August 2021 | type = Developer network | publisher = Microsoft}}.

{{CProLang}}
{{C++ programming language}}

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