std::search_n
From Cppreference
| Defined in header
<algorithm> | ||
| template< class ForwardIterator, class Size, class T >
ForwardIterator1 search_n( ForwardIterator first, ForwardIterator last, | (1) | |
| template< class ForwardIterator, class Size, class T, class BinaryPredicate >
ForwardIterator1 search_n( ForwardIterator first, ForwardIterator last, | (2) | |
Searches the range [first, last) for the first sequence of count identical elements, each equal to the given value value. The first version uses operator== to compare the elements, the second version uses the given binary predicate p.
Contents |
Parameters
| first, last | - | the range of elements to examine | |||||||||
| count | - | the length of the sequence to search for | |||||||||
| value | - | the value of the elements to search for | |||||||||
| 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 const &, but the function must not modify the objects passed to it. | |||||||||
Return value
iterator to the beginning of the found sequence in the range [first, last). If no such sequence is found, last is returned.
Equivalent function
| First version: |
|---|
template<class ForwardIterator, class Size, class T> ForwardIterator1 search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value) { Size curr_count = 0; ForwardIterator result, t_last = first; std::advance(t_last, std::distance(first, last) - count + 1); for (; first != t_last; first++) { curr_count = 0; result = first; while (*first == value) { curr_count++; if (curr_count == count) { return result; } ++first; } } return last; } |
| Second version: |
template<class ForwardIterator, class Size, class T, class BinaryPredicate> ForwardIterator1 search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value, BinaryPredicate p) { Size curr_count = 0; ForwardIterator result, t_last = first; std::advance(t_last, std::distance(first, last) - count + 1); for (; first != t_last; first++) { curr_count = 0; result = first; while (p(*first == value)) { curr_count++; if (curr_count == count) { return result; } ++first; } } return last; } |
Example
| This section is incomplete |
Complexity
linear in the distance between first and last
See also
| finds the last sequence of elements in a certain range (function template) | ||
| finds the first element satisfying specific criteria (function template) | ||
| searches for a range of elements (function template) | ||
