std::unique_copy
De cppreference.com
<metanoindex/>
<tbody> </tbody>| Definido no cabeçalho <algorithm>
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template< class InputIt, class OutputIt > ForwardIt unique_copy( InputIt first, InputIt last, OutputIt d_first ); |
(1) | |
template< class InputIt, class OutputIt, class BinaryPredicate > ForwardIt unique_copy( InputIt first, InputIt last, OutputIt d_first, BinaryPredicate p ); |
(2) | |
Copia os elementos da gama
[first, last), para outro intervalo de início d_first de tal maneira que não existem elementos consecutivos iguais. Apenas o primeiro elemento de cada grupo de elementos iguais é copiado. A primeira versão utiliza operator== para comparar os elementos, a segunda versão usa o predicado binário dado p.Original:
Copies the elements from the range
[first, last), to another range beginning at d_first in such a way that there are no consecutive equal elements. Only the first element of each group of equal elements is copied. The first version uses operator== to compare the elements, the second version uses the given binary predicate p.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.
Parâmetros
| first, last | - | a gama de elementos ao processo
Original: the range of elements to process The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| d_first | - | o início do intervalo de destino
Original: the beginning of the destination range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| p | - | binary predicate which returns true if the elements should be treated as equal. The signature of the predicate function should be equivalent to the following:
The signature does not need to have |
| Type requirements | ||
-InputIt must meet the requirements of InputIterator.
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-OutputIt must meet the requirements of OutputIterator.
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-The type of dereferenced InputIt must meet the requirements of CopyAssignable.
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-The type of dereferenced InputIt must meet the requirements of CopyConstructible. if neither InputIt nor OutputIt satisfies ForwardIterator
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Valor de retorno
Iterator saída para o elemento passado o último elemento escrito
Original:
Output iterator to the element past the last written element
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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Possível implementação
| First version |
|---|
template<class ForwardIt, class OutputIt>
ForwardIt unique_copy(ForwardIt first, ForwardIt last,
OutputIt d_first)
{
if (first == last)
return d_first;
*d_first = *first;
while (++first != last) {
if (!(*d_first == *first)) {
*(++d_first) = *first;
}
}
return ++d_first;
}
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| Second version |
template<class ForwardIt, class OutputIt, class BinaryPredicate>
ForwardIt unique_copy(ForwardIt first, ForwardIt last,
OutputIt d_first, BinaryPredicate p)
{
if (first == last)
return d_first;
*d_first = *first;
while (++first != last) {
if (!p(*result, *first)) {
*(++d_first) = *first;
}
}
return ++d_first;
}
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Exemplo
As guarnições de programa a seguir todos os espaços múltiplos consecutivos em uma const string e imprime o resultado
Original:
The following program trims all multiple consecutive spaces in a const string and prints the result
The text has been machine-translated via Google Translate.
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#include <string>
#include <iostream>
#include <algorithm>
#include <iterator>
int main()
{
std::string s1 = "The string with many spaces!";
std::cout << "before: " << s1 << '\n';
std::string s2;
std::unique_copy(s1.begin(), s1.end(), std::back_inserter(s2),
[](char c1, char c2){ return c1 == ' ' && c2 == ' '; });
std::cout << "after: " << s2 << '\n';
}
Saída:
before: The string with many spaces!
after: The string with many spaces!
Complexidade
linear, em que a distância entre
first e lastOriginal:
linear in the distance between
first and lastThe 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.