std::pair

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)
Dynamic memory management
Error handling
Program utilities
Variadic functions
Library feature-test macros
Date and time
Function objects
initializer_list (C++11)
bitset
hash (C++11)
integer_sequence (C++14)
Relational operators (deprecated in C++20)
rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=
Comparisons (C++20)
strong_order weak_order partial_order strong_equal weak_equal	strong_ordering weak_ordering partial_ordering strong_equality weak_equality	is_eqis_neqis_ltis_lteqis_gtis_gteq
common_comparison_category
Common vocabulary types
pair tuple (C++11) apply (C++17) make_from_tuple (C++17)	optional (C++17) any (C++17) variant (C++17)
Swap, forward and move
swap
exchange (C++14)
forward (C++11)
move (C++11)
move_if_noexcept (C++11)
Elementary string conversions
to_chars (C++17)
from_chars (C++17)
chars_format (C++17)
Type operations
declval (C++11)
as_const (C++17)
launder (C++17)

 

std::pair

Member functions

pair::pair

pair::operator=

pair::swap

Non-member functions

make_pair

operator==operator!=operator<operator<=operator>operator>=

std::swap

get (C++11)

Deduction guides(C++17)

Helper classes

tuple_size (C++11)

tuple_element (C++11)

 

Defined in header <utility>
template<     class T1,     class T2 > struct pair;

std::pair is a struct template that provides a way to store two heterogeneous objects as a single unit. A pair is a specific case of a std::tuple with two elements.

If std::is_trivially_destructible_v<T1> && std::is_trivially_destructible_v<T2> is true, the destructor of pair is trivial.

(since C++17)

Template parameters

T1, T2

-

the types of the elements that the pair stores.

Member types

Member type	Definition
first_type	T1
second_type	T2

Member objects

Member name	Type
first	T1
second	T2

Member functions

(constructor)	constructs new pair (public member function)
operator=	assigns the contents (public member function)
swap (C++11)	swaps the contents (public member function)

Non-member functions

make_pair	creates a pair object of type, defined by the argument types (function template)
operator==operator!=operator<operator<=operator>operator>=	lexicographically compares the values in the pair (function template)
std::swap(std::pair) (C++11)	specializes the std::swap algorithm (function template)
std::get(std::pair) (C++11)	accesses an element of a pair (function template)

Helper classes

std::tuple_size<std::pair> (C++11)	obtains the size of a pair (class template specialization)
std::tuple_element<std::pair> (C++11)	obtains the type of the elements of pair (class template specialization)

See also

tuple (C++11)	implements fixed size container, which holds elements of possibly different types (class template)
tie	creates a tuple of lvalue references or unpacks a tuple into individual objects (function template)