std::default_searcher (3) - Linux Man Pages

std::default_searcher: std::default_searcher

NAME

std::default_searcher - std::default_searcher

Synopsis


Defined in header <functional>
template< class ForwardIt, class BinaryPredicate = std::equal_to<> > (since C++17)
class default_searcher;


A class suitable for use with Searcher overload of std::search that delegates the search operation to the pre-C++17 standard library's std::search.
default_searcher is CopyConstructible and CopyAssignable.

Member functions


 std::default_searcher::default_searcher


default_searcher( ForwardIt pat_first, (since C++17)
ForwardIt pat_last, (until C++20)
BinaryPredicate pred = BinaryPredicate());
constexpr default_searcher( ForwardIt pat_first,
ForwardIt pat_last, (since C++20)
BinaryPredicate pred = BinaryPredicate());


Constructs a default_searcher by storing copies of pat_first, pat_last, and pred

Parameters


pat_first, pat_last - a pair of iterators designating the string to be searched for
pred - a callable object used to determine equality

Exceptions


Any exceptions thrown by the copy constructors of BinaryPredicate or ForwardIt.


 std::default_searcher::operator()


template< class ForwardIt2 > (since C++17)
std::pair<ForwardIt2, ForwardIt2> (until C++20)
operator()( ForwardIt2 first, ForwardIt2 last ) const;
template< class ForwardIt2 >
constexpr std::pair<ForwardIt2, ForwardIt2> (since C++20)
operator()( ForwardIt2 first, ForwardIt2 last ) const;


The member function called by the Searcher overload of std::search to perform a search with this searcher.
Returns a pair of iterators i, j, where i is std::search(first, last, pat_first, pat_last, pred) and j is std::next(i, std::distance(pat_first, pat_last)) unless std::search returned last (no match), in which case j equals last as well.

Parameters


first, last - a pair of iterators designating the string to be examined

Return value


A pair of iterators to the first and one past last positions in [first, last) where a subsequence that compares equal to [pat_first, pat_last) as defined by pred is located, or a pair of copies of last otherwise.

Example


// Run this code


  #include <iostream>
  #include <string>
  #include <algorithm>
  #include <functional>


  int main()
  {
      std::string in = "Lorem ipsum dolor sit amet, consectetur adipiscing elit,"
                       " sed do eiusmod tempor incididunt ut labore et dolore magna aliqua";
      std::string needle = "pisci";
      auto it = std::search(in.begin(), in.end(),
                     std::default_searcher(
                         needle.begin(), needle.end()));
      if(it != in.end())
          std::cout << "The string " << needle << " found at offset "
                    << it - in.begin() << '\n';
      else
          std::cout << "The string " << needle << " not found\n";
  }

Output:


  The string pisci found at offset 43

See also


       searches for a range of elements
search (function template)