< cpp‎ | algorithm
Defined in header <algorithm>
template< class InputIt, class Size, class OutputIt >
OutputIt copy_n( InputIt first, Size count, OutputIt result );
(since C++11)

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


[edit] Parameters

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

[edit] Return value

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

[edit] Complexity

Exactly count assignments, if count>0.

[edit] Possible implementation

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;

[edit] Example

#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';



[edit] See also

copies a range of elements to a new location
(function template)
parallelized version of std::copy_n
(function template)