std::tuple_size<std::pair>

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C++

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Espressioni regolari (C++11)

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Utilità libreria

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initializer_list (C++11)

bitset

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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)

 

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Elemento definito nell'header <utility>
template< class T1, class T2 > struct tuple_size<std::pair<T1, T2>>;		(dal C++11)

The partial specialization of std::tuple_size for pairs provides a compile-time way to obtain the number of elements in a pair, which is always 2, using tuple-like syntax.

Members
value [statico]	integral constant with value 2 (pubblico membro statico costante)

Esempio

#include <iostream>
#include <utility>
#include <tuple>

template<class T>
void test(T t)
{
    int a[std::tuple_size<T>::value]; // can be used at compile time
    std::cout << std::tuple_size<T>::value << '\n'; // or at run time
}

int main()
{
    test(std::make_tuple(1, 2, 3.14));
    test(std::make_pair(1, 3.14));
}

Output:

3
2

Vedi anche

tuple_size	ottiene la dimensione della tuple al momento della compilazione Original: obtains the size of tuple at compile time The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe modello di specializzazione)
std::tuple_size<std::array>	ottiene la dimensione di un array Original: obtains the size of an array The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe modello di specializzazione)
std::tuple_element<std::pair> (C++11)	ottiene il tipo di elementi di pair Original: obtains the type of the elements of pair The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe modello di specializzazione)