c++ - Is there a function that is to std::search what std::count is to std::find? -

if title sounds weird here explanation:

if have range a, , want count how many times range b appeared in range a, there std:: function it?

if no, there simple way (ofc can manually loop using std::search - i'm talking more elegant)?

i think you'll need build own. here's comes mind implementation.

template <typename iterator1, typename iterator2> size_t subsequence_count(iterator1 haystack_begin, iterator1 haystack_end, iterator2 needle_begin, iterator2 needle_end) {     size_t count = 0;     while (true) {         haystack_begin = std::search(haystack_begin, haystack_end, needle_begin, needle_end);         if (haystack_begin == haystack_end)             return count;         count++;         haystack_begin++;     } }  template <typename iterator1, typename iterator2, typename binarypredicate> size_t subsequence_count(iterator1 haystack_begin, iterator1 haystack_end, iterator2 needle_begin, iterator2 needle_end, binarypredicate predicate) {     size_t count = 0;     while (true) {         haystack_begin = std::search(haystack_begin, haystack_end, needle_begin, needle_end, predicate);         if (haystack_begin == haystack_end)             return count;         count++;         haystack_begin++;     } } 

some code using this:

int main() {     std::vector<int> haystack = {1, 19, 7, 23, 2, 19, 19, 19, 19};     std::vector<int> needle   = {19, 19};      assert(subsequence_count(begin(haystack), end(haystack), begin(needle), end(needle) == 3); }