std::partition_copy — cppreference.com

De cppreference.com

Déclaré dans l'en-tête `<algorithm>`
`template< class InputIt, class OutputIt1, class OutputIt2, class UnaryPredicate > std::pair<OutputIt1, OutputIt2> partition_copy(InputIt first, InputIt last, OutputIt1 d_first_true, OutputIt2 d_first_false, UnaryPredicate p);`		(depuis C++11)

Copie les éléments qui satisfont le prédicat p de la plage [first, last) au début plage à d_first_true, et copie les éléments qui ne satisfont pas p au début plage à d_first_false .

Original:

Copies the elements that satisfy the predicate p from the range [first, last) to the range beginning at d_first_true, and copies the elements that do not satisfy p to the range beginning at d_first_false.

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

Paramètres

first, last	-	la plage d'éléments à trier Original: the range of elements to sort The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
d_first_true	-	le début de la plage de sortie pour les éléments qui satisfont p Original: the beginning of the output range for the elements that satisfy p The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
d_first_false	-	le début de la plage de sortie pour les éléments qui ne satisfont pas p Original: the beginning of the output range for the elements that do not satisfy p The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
p	-	prédicat unéaire qui retourne `true` si l'élément doit être placé dans d_first_true Original: if the element should be placed in d_first_true The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. . L'expression `p(v)` doit pouvoir être convertie à `bool` pour tout argument `v` de type (possiblement const) `VT`, où `VT` est le type de valeur de `InputIt`, inconditionellement de value category, et ne doit pas modifier `v`. Ainsi, un type-paramètre `VT&`n'est pas permis ainsi que pour `VT` sauf pour `VT` un déplacement est équivalent à une copie (depuis C++11).
Type requirements
-`InputIt` must meet the requirements of `InputIterator`.
-`OutputIt1` must meet the requirements of `OutputIterator`.
-`OutputIt2` must meet the requirements of `OutputIterator`.

Retourne la valeur

Un pair construit à partir de l'itérateur à la fin de l'intervalle d_first_true et l'itérateur à la fin de l'intervalle d_first_false .

Original:

A pair constructed from the iterator to the end of the d_first_true range and the iterator to the end of the d_first_false range.

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

Complexité

Exactement distance(first, last) applications de p .

Original:

Exactly distance(first, last) applications of p.

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

Mise en œuvre possible

template<class InputIt, class OutputIt1,
         class OutputIt2, class UnaryPredicate>
std::pair<OutputIt1, OutputIt2>
    partition_copy(InputIt first, InputIt last,
                   OutputIt1 d_first_true, OutputIt2 d_first_false,
                   UnaryPredicate p)
{
    while (first != last) {
        if (p(*first)) {
            *d_first_true = *first;
            ++d_first_true;
        } else {
            *d_first_false = *first;
            ++d_first_false;
        }
        ++first;
    }
    return std::pair<OutputIt1, OutputIt2>(d_first_true, d_first_false);
}

Exemple

#include <iostream>
#include <algorithm>
#include <utility>

int main()
{
    int arr [10] = {1,2,3,4,5,6,7,8,9,10};
    int true_arr [5] = {0};
    int false_arr [5] = {0};

    std::partition_copy(std::begin(arr), std::end(arr), std::begin(true_arr),std::begin(false_arr),
                        [] (int i) {return i > 5;});

    std::cout << "true_arr: ";
    for (auto it = std::begin(true_arr); it != std::end(true_arr); ++it) {
        std::cout << *it << ' ';
    }
    std::cout << '\n'; 

    std::cout << "false_arr: ";
    for (auto it = std::begin(false_arr); it != std::end(false_arr); ++it) {
        std::cout << *it << ' ';
    }
    std::cout << '\n'; 

    return 0;

}

Résultat :

true_arr: 6 7 8 9 10
false_arr: 1 2 3 4 5

Voir aussi


	divise une série d'éléments en deux groupes Original: divides a range of elements into two groups The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique) [edit]

	divise les éléments en deux groupes, tout en préservant leur ordre relatif Original: divides elements into two groups while preserving their relative order The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique) [edit]