std::copy_n

 

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all_ofany_ofnone_of (C++11)(C++11)(C++11) for_each countcount_if mismatch equal	findfind_iffind_if_not (C++11) find_end find_first_of adjacent_find search search_n
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copycopy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) fill fill_n transform generate generate_n removeremove_if remove_copyremove_copy_if	replacereplace_if replace_copyreplace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffleshuffle  (C++11) unique unique_copy
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Definido no cabeçalho <algorithm>
template<class InputIt, class Size, class OutputIt > OutputIt copy_n( InputIt first, Size count, OutputIt result );

Copies exactly count values from the range beginning at first to the range beginning at result, if count>0. Does nothing otherwise.

Parâmetros

first	-	the beginning of the range of elements to copy from
count	-	number of the elements to copy
result	-	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.
Type requirements
- InputIt must meet the requirements of InputIterator.
- OutputIt must meet the requirements of OutputIterator.

Valor de retorno

Iterator in the destination range, pointing past the last element copied if count>0 or first otherwise.

Complexidade

Exactly count assignments, if count>0.

Possível implementação

template<class InputIt, class Size, class OutputIt> OutputIt copy_n(InputIt first, Size count, OutputIt result){if(count >0){*result++=*first;for(Size i =1; i < count;++i){*result++=*++first;}}return result;}

Exemplo

#include <iostream>#include <string>#include <algorithm>#include <iterator>   int main(){std::string in ="1234567890";std::string out;   std::copy_n(in.begin(), 4, std::back_inserter(out));std::cout<< out <<'\n';}

Saída:

1234

Veja também

copy copy_if (C++11)	Copia um intervalo de elementos para um novo local Original: copies a range of elements to a new location The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de função)