std::default_searcher(3)

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.
   std::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 std::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 <algorithm>
 #include <functional>
 #include <iomanip>
 #include <iostream>
 #include <string_view>
 int main()
 {
     constexpr std::string_view in =
         "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed "
         "do eiusmod tempor incididunt ut labore et dolore magna aliqua";
     const std::string_view 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 " << std::quoted(needle) << " found at offset "
                   << it - in.begin() << '\n';
     else
         std::cout << "The string " << std::quoted(needle) << " not found\n";
 }

Output:
 The string "pisci" found at offset 43

See also
   search searches for a range of elements
                        (function template)
   boyer_moore_searcher Boyer-Moore search algorithm implementation
   (C++17) (class template)
   boyer_moore_horspool_searcher Boyer-Moore-Horspool search algorithm implementation
   (C++17) (class template)