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    std::prev

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    <metanoindex/>

     
    C++
     
    Bibliothèque Iterator
    Primitives Iterator
    Original:
    Iterator primitives
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    iterator_traits
    input_iterator_tag
    output_iterator_tag
    forward_iterator_tag
    bidirectional_iterator_tag
    random_access_iterator_tag
    iterator
    Adaptateurs Iterator
    Original:
    Iterator adaptors
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    reverse_iterator
    Itérateurs de flux
    Original:
    Stream iterators
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    istream_iterator
    ostream_iterator
    istreambuf_iterator
    ostreambuf_iterator
    Opérations Iterator
    Original:
    Iterator operations
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    advance
    distance
    prev (C++11)
    next (C++11)
    Gamme d'accès
    Original:
    Range access
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    begin (C++11)
    end (C++11)
     
    <tbody> </tbody>
    Déclaré dans l'en-tête <iterator>
    template< class BidirIt > BidirIt prev( BidirIt it, typename std::iterator_traits<BidirIt>::difference_type n = 1 );
    		 (depuis C++11)
    Retour le prédécesseur de nth it itérateur .
    Original:
    Return the nth predecessor of iterator it.
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    Paramètres

    it -
    un itérateur
    Original:
    an iterator
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    n -
    nombre de it éléments devraient être descendu
    Original:
    number of elements it should be descended
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    Type requirements
    -
    BidirIt must meet the requirements of BidirectionalIterator.

    Retourne la valeur

    Le prédécesseur de nth it itérateur .
    Original:
    The nth predecessor of iterator it.
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    Mise en œuvre possible

    template<class BidirIt>
BidirIt prev(BidirIt it, typename std::iterator_traits<BidirIt>::difference_type n = 1)
{
    std::advance(it, -n);
    return it;
}

    Exemple

    #include <iostream>
#include <iterator>
#include <vector>

int main() 
{
    std::vector<int> v{ 3, 1, 4 };
    
    auto it = v.end();

    auto pv = std::prev(it, 2);

    std::cout << *pv << '\n';
}

    Résultat : 

    1

    Voir aussi

    (C++11)
    incrémenter un itérateur
    Original:
    increment an iterator
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    (fonction) [edit]
    avance un itérateur par distance donnée
    Original:
    advances an iterator by given distance
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    (fonction) [edit]