|Category: algorithms ||Component type: function |
template <class InputIterator, class Size, class OutputIterator>
OutputIterator copy_n(InputIterator first, Size count,
Copy_n copies elements from the range
[first, first + n) to the range
[result, result + n). That is, it performs the assignments
*result = *first,
*(result + 1) = *(first + 1), and so on. Generally, for every integer
0 up to (but not including)
copy_n performs the assignment
*(result + i) = *(first + i). Assignments are performed in forward order, i.e. in order of increasing
The return value is
result + n.
Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h. This function is an SGI extension; it is not part of the C++ standard.
Requirements on types
InputIterator is a model of InputIterator.
OutputIterator is a model of OutputIterator.
Size is an integral type.
InputIterator's value type is convertible to a type in OutputIterator's set of value types.
n >= 0.
[first, first + n) is a valid range.
result is not an iterator within the range
[first, first + n).
[result, result + n) is a valid range.
n assignments are performed.
iota(V.begin(), V.end(), 1);
copy_n(V.begin(), V.size(), L.begin());
assert(equal(V.begin(), V.end(), L.begin()));
Copy_n is almost, but not quite, redundant. If
first is an InputIterator, as opposed to a ForwardIterator, then the
copy_n operation can't be expressed in terms of