std::copy, std::copy_if
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<tbody> </tbody>| Dclar dans l'en-tte <algorithm>
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template< class InputIt, class OutputIt > OutputIt copy( InputIt first, InputIt last, OutputIt d_first ); |
(1) | |
template< class InputIt, class OutputIt, class UnaryPredicate > OutputIt copy_if( InputIt first, InputIt last, OutputIt d_first, UnaryPredicate pred ); |
(2) | (depuis C++11) |
Copier les lments de la gamme, dfini par
[first, last), dans un autre intervalle au dbut d_first. La deuxime fonction ne copie que les lments pour lesquels le prdicat renvoie pred true . Original:
Copies the elements in the range, defined by
[first, last), to another range beginning at d_first. The second function only copies the elements for which the predicate pred returns true. 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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Paramtres
| first, last | - | l'ventail des lments copier
Original: the range of elements to copy The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| d_first | - | le dbut de la plage de destination. Si
d_first est dans [first, last), std::copy_backward doit tre utilis la place de std::copy . Original: the beginning of the destination range. If d_first is within [first, last), std::copy_backward must be used instead of std::copy. The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| pred | - | prdicat unaire qui retourne true pour les lments requis . Original: for the required elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. L'expression |
| Type requirements | ||
-InputIt must meet the requirements of InputIterator.
| ||
-OutputIt must meet the requirements of OutputIterator.
| ||
Retourne la valeur
Itrateur de sortie de l'lment dans la zone de destination, une aprs le dernier lment copi .
Original:
Output iterator to the element in the destination range, one past the last element copied.
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Complexit
1)
Exactement
last - first missionsOriginal:
Exactly
last - first assignmentsThe text has been machine-translated via Google Translate.
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2)
Exactement
last - first applications du prdicatOriginal:
Exactly
last - first applications of the predicateThe text has been machine-translated via Google Translate.
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Notes
Dans la pratique, les implmentations de
std::copy vitent les affectations multiples et utilisent des fonctions de copie binaire telles que std::memmove si le type de valeur est TriviallyCopyableOriginal:
In practice, implementations of
std::copy avoid multiple assignments and use bulk copy functions such as std::memcpy if the value type is TriviallyCopyableThe text has been machine-translated via Google Translate.
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Mise en uvre possible
| First version |
|---|
template<class InputIt, class OutputIt>
OutputIt copy(InputIt first, InputIt last,
OutputIt d_first)
{
while (first != last) {
*d_first++ = *first++;
}
return d_first;
}
|
| Second version |
template<class InputIt, class OutputIt, class UnaryPredicate>
OutputIt copy_if(InputIt first, InputIt last,
OutputIt d_first, UnaryPredicate pred)
{
while (first != last) {
if(pred(*first))
*d_first++ = *first;
first++;
}
return d_first;
}
|
Exemple
Le code suivant utilise la copie la fois sur le contenu d'un vecteur l'autre et d'afficher le vecteur rsultant:
Original:
The following code uses copy to both copy the contents of one vector to another and to display the resulting vector:
The text has been machine-translated via Google Translate.
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#include <algorithm>
#include <iostream>
#include <vector>
#include <iterator>
int main()
{
std::vector<int> from_vector;
for (int i = 0; i < 10; i++) {
from_vector.push_back(i);
}
std::vector<int> to_vector(10);
std::copy(from_vector.begin(), from_vector.end(), to_vector.begin());
std::cout << "to_vector contains: ";
std::copy(to_vector.begin(), to_vector.end(),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
}
Rsultat :
to_vector contains: 0 1 2 3 4 5 6 7 8 9
Voir aussi
copie une plage d'lments dans l'ordre inverse Original: copies a range of elements in backwards order The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction gnrique) | |
Copie une srie d'lments en omettant ceux qui satisfont certains critres Original: copies a range of elements omitting those that satisfy specific criteria The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction gnrique) | |