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)