std::pair::pair

 

C++

Linguaggio

Concetti

Libreria di Utilità

Stringhe

Contenitori

Algoritmi

Iteratori

Libreria matematca

Input/output

Localizzazione

Espressioni regolari (C++11)

Operazioni atomicche (C++11)

Multithreading (C++11)

 

Utilità libreria

Tipo di supporto (basic types, RTTI, type traits)

Gestione della memoria dinamica

La gestione degli errori

Programma di utilità

Funzioni variadic

Data e ora

Funzione oggetti

initializer_list (C++11)

bitset

hash (C++11)

Gli operatori relazionali Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

Coppie e tuple Original: Pairs and tuples The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

Swap, in avanti e spostare Original: Swap, forward and move The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

swap

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

declval (C++11)

 

std::pair

Membri funzioni Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

pair::pair

pair::operator=

pair::swap

Non membri funzioni Original: Non-member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

make_pair

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

std::swap

get (C++11)

Helper classi Original: Helper classes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

tuple_size (C++11)

tuple_element (C++11)

 

pair(); constexpr pair();	(1)	(C fino + 11) (dal C++11)
pair( const T1& x, const T2& y );	(2)
template< class U1, class U2 > pair( U1&& x, U2&& y );	(3)	(dal C++11)
template< class U1, class U2 > pair( const pair<U1,U2>& p );	(4)
template< class U1, class U2 > pair( pair<U1,U2>&& p );	(5)	(dal C++11)
template< class... Args1, class... Args2 > pair( std::piecewise_construct_t,       std::tuple<Args1...> first_args,       std::tuple<Args2...> second_args );	(6)	(dal C++11)
pair( const pair& p ) = default;	(7)
pair( pair&& p ) = default;	(8)	(dal C++11)

Costruisce una nuova coppia.

Original:

Constructs a new pair.

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1)

Costruttore di default. Valore-inizializza entrambi gli elementi della coppia, first e second.

Original:

Default constructor. Value-initializes both elements of the pair, first and second.

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2)

Inizializza first con x e second con y.

Original:

Initializes first with x and second with y.

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3)

Inizializza first con std::forward<U1>(x) e second con std::forward<U2>(y).

Original:

Initializes first with std::forward<U1>(x) and second with std::forward<U2>(y).

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4)

Inizializza first con p.first e second con p.second.

Original:

Initializes first with p.first and second with p.second.

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5)

Inizializza first con std::move<U1>(p.first) e second con std::move<U2>(p.second).

Original:

Initializes first with std::move<U1>(p.first) and second with std::move<U2>(p.second).

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6)

Contratti a termine gli elementi della first_args al costruttore di first e inoltra gli elementi della second_args al costruttore di second. Questo è l'unico costruttore non predefinito che può essere utilizzato per creare una coppia di non-copiabili non mobili tipi.

Original:

Forwards the elements of first_args to the constructor of first and forwards the elements of second_args to the constructor of second. This is the only non-default constructor that can be used to create a pair of non-copyable non-movable types.

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7)

Costruttore di copia è implicitamente generato.

Original:

Copy constructor is implicitly generated.

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8)

Costruttore Move è implicitamente generato.

Original:

Move constructor is implicitly generated.

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Parametri

x	-	valore per inizializzare il primo elemento di questa coppia Original: value to initialize the first element of this pair The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
y	-	valore per inizializzare il secondo elemento di questa coppia Original: value to initialize the second element of this pair The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
p	-	coppia di valori utilizzati per inizializzare entrambi gli elementi di questa coppia Original: pair of values used to initialize both elements of this pair The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
first_args	-	tupla di argomenti del costruttore per inizializzare il primo elemento di questa coppia Original: tuple of constructor arguments to initialize the first element of this pair The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
second_args	-	tupla di argomenti del costruttore per inizializzare il secondo elemento di questa coppia Original: tuple of constructor arguments to initialize the second element of this pair The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Esempio

#include <utility>
#include <string>
#include <complex>
#include <tuple>
#include <iostream>
int main()
{
    std::pair<int, float> p1;
    std::cout << "Value-initialized: "
              << p1.first << ", " << p1.second << '\n';
 
    std::pair<int, double> p2(42, 0.123);
    std::cout << "Initialized with two values: "
              << p2.first << ", " << p2.second << '\n';
 
    std::pair<char, int> p4(p2);
    std::cout << "Implicitly converted: "
              << p4.first << ", " << p4.second << '\n';
 
    std::pair<std::complex<double>, std::string> p6(
                    std::piecewise_construct, 
                    std::forward_as_tuple(0.123, 7.7),
                    std::forward_as_tuple(10, 'a'));
    std::cout << "Piecewise constructed: "
              << p6.first << ", " << p6.second << '\n';
}

Output:

Value-initialized: 0, 0
Initialized with two values: 42, 0.123
Implicitly converted: *, 0
Piecewise constructed: (0.123,7.7), aaaaaaaaaa

Vedi anche

make_pair	crea un oggetto di tipo pair, definita dai tipi di argomenti Original: creates a pair object of type, defined by the argument types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funzione di modello)