std::copy, std::copy_if
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Defined in header <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, |
(2) | (desde C++11) |
Copia los elementos en el intervalo, definidos por
[first, last)
, a otro principio rango en d_first
. La segunda función sólo copia los elementos para los que el predicado devuelve 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.
You can help to correct and verify the translation. Click here for instructions.
Contenido |
[editar] Parámetros
first, last | - | la gama de elementos a copiar
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 | - | el comienzo del rango de destino. Si está dentro de
d_first [first, last) , std::copy_backward debe ser utilizado en lugar 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 | - | unary predicate which returns true para los elementos requeridos . 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. The signature of the predicate function should be equivalent to the following: bool pred(const Type &a); The signature does not need to have const &, but the function must not modify the objects passed to it. |
Type requirements | ||
-InputIt must meet the requirements of InputIterator .
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-OutputIt must meet the requirements of OutputIterator .
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[editar] Valor de retorno
Iterador de salida para el elemento en el área de destino, uno pasado el último elemento copiado .
Original:
Output iterator to the element in the destination range, one past the last element copied.
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[editar] Complejidad
1)Exactamente
2) last - first
asignacionesOriginal:
Exactly
last - first
assignmentsThe text has been machine-translated via Google Translate.
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Exactamente
last - first
aplicaciones del predicadoOriginal:
Exactly
last - first
applications of the predicateThe text has been machine-translated via Google Translate.
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[editar] Notas
En la práctica, las implementaciones de
std::copy
evitar asignaciones múltiples y el uso de funciones de copia masiva como std::memcpy si el tipo de valor es TriviallyCopyable
Original:
In practice, implementations of
std::copy
avoid multiple assignments and use bulk copy functions such as std::memcpy if the value type is TriviallyCopyable
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[editar] Posible implementación
First version |
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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; } |
[editar] Ejemplo
El código siguiente utiliza copia a ambos copia el contenido de un vector a otro y para mostrar el vector resultante:
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.
You can help to correct and verify the translation. Click here for instructions.
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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; }
Output:
to_vector contains: 0 1 2 3 4 5 6 7 8 9
[editar] Ver también
Copia un intervalo de elementos para atrás 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. (función de plantilla) | |
Copia un intervalo de elementos omitiendo los que satisfacen criterios específicos 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. (función de plantilla) |