std::input_iterator_tag, std::output_iterator_tag, std::forward_iterator_tag, std::bidirectional_iterator_tag, std::random_access_iterator_tag
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<metanoindex/>
<tbody> </tbody>| Definido no cabeçalho <iterator>
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struct input_iterator_tag { }; |
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struct output_iterator_tag { }; |
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struct forward_iterator_tag : public input_iterator_tag { }; |
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struct bidirectional_iterator_tag : public forward_iterator_tag { }; |
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struct random_access_iterator_tag : public bidirectional_iterator_tag { }; |
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Os tipos de vazios
std::input_iterator_tag, std::output_iterator_tag, forward_iterator_tag, bidirectional_iterator_tag, e random_access_iterator_tag são usados para selecionar algoritmos apropriados com base na categoria de um iterador. Para cada tipo de iterador, um std::iterator_traits<Iterator>::iterator_category typedef está disponível, o que é um alias para um desses tipos de marcas cinco.Original:
The empty types
std::input_iterator_tag, std::output_iterator_tag, forward_iterator_tag, bidirectional_iterator_tag, and random_access_iterator_tag are used to select appropriate algorithms based on the category of an iterator. For every iterator type, a typedef std::iterator_traits<Iterator>::iterator_category is available, which is an alias to one of these five tag types.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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Exemplo
Técnica comum para a seleção algoritmo baseado em tags categoria iterador é usar uma função de despachante (a alternativa é std :: enable_if)
Original:
Common technique for algorithm selection based on iterator category tags is to use a dispatcher function (the alternative is std::enable_if)
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You can help to correct and verify the translation. Click here for instructions.
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#include <iostream>
#include <vector>
#include <list>
#include <iterator>
template< class BDIter >
void alg(BDIter, BDIter, std::bidirectional_iterator_tag)
{
std::cout << "alg() called for bidirectional iterator\n";
}
template <class RAIter>
void alg(RAIter, RAIter, std::random_access_iterator_tag)
{
std::cout << "alg() called for random-access iterator\n";
}
template< class Iter >
void alg(Iter first, Iter last)
{
alg(first, last,
typename std::iterator_traits<Iter>::iterator_category());
}
int main()
{
std::vector<int> v;
alg(v.begin(), v.end());
std::list<int> l;
alg(l.begin(), l.end());
// std::istreambuf_iterator<char> i1(std::cin), i2;
// alg(i1, i2); // compile error: no matching function for call
}
Saída:
alg() called for random-access iterator
alg() called for bidirectional iterator
Veja também
o iterador básica Original: the basic iterator The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de classe) | |
fornece uma interface uniforme para as propriedades de uma iteração Original: provides uniform interface to the properties of an iterator The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de classe) | |