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>| Déclaré dans l'en-tête <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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Les types vides
std::input_iterator_tag, std::output_iterator_tag, forward_iterator_tag, bidirectional_iterator_tag et random_access_iterator_tag sont utilisés pour sélectionner des algorithmes appropriés en fonction de la catégorie d'un itérateur. Pour chaque type itérateur, un std::iterator_traits<Iterator>::iterator_category typedef est disponible, ce qui est un alias de l'un de ces types de balises cinq .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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Exemple
Technique courante pour la sélection de l'algorithme basé sur les balises catégorie itérateur est d'utiliser une fonction de régulateur (l'alternative est 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)
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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#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
}
Résultat :
alg() called for random-access iterator
alg() called for bidirectional iterator
Voir aussi
l'itérateur de base 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. (classe générique) | |
fournit une interface uniforme pour les propriétés d'un itérateur 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. (classe générique) | |