std::experimental:: default_searcher, std::experimental:: make_default_searcher

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C++
Experimental
Library fundamentals
Defined in header <experimental/functional>
template < class ForwardIterator1, class BinaryPredicate = std:: equal_to <> >
class default_searcher ;
(library fundamentals TS)

A class suitable for use with std::experimental::search that delegates the search operation to the standard library's std::search .

default_searcher is CopyConstructible and CopyAssignable .

Member functions

std::experimental::default_searcher:: default_searcher

default_searcher ( ForwardIterator pat_first,

ForwardIterator pat_last,

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 ForwardIterator .

std::experimental::default_searcher:: operator()

template < class ForwardIterator2 >
ForwardIterator2 operator ( ) ( ForwardIterator2 first, ForwardIterator2 last ) const ;
(until C++17)
template < class ForwardIterator2 >

std:: pair < ForwardIterator2, ForwardIterator2 >

operator ( ) ( ForwardIterator2 first, ForwardIterator2 last ) const ;
(since C++17)

The member function called by std::experimental::search to perform a search with this searcher.

Equivalent to std:: search ( first, last, pat_first, pat_last, pred ) ; .

(until C++17)

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.

(until C++17)

Parameters

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

Return value

Iterator to the first position in [ first , last ) where a subsequence that compares equal to [ pat_first , pat_last ) as defined by pred is located, or a copy of last otherwise.

(until C++17)

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.

(since C++17)

Helper Functions

template < class ForwardIterator, class BinaryPredicate = std:: equal_to <> >

default_searcher < ForwardIterator, BinaryPredicate > make_default_searcher (
ForwardIterator pat_first,
ForwardIterator pat_last,

BinaryPredicate pred = BinaryPredicate ( ) ) ;
(library fundamentals TS)

Helper function that constructs a std::experimental::default_searcher using template argument deduction. Equivalent to return default_searcher < ForwardIterator, BinaryPredicate > ( pat_first, pat_last, 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

Return value

A default_searcher constructed with the arguments pat_first , pat_last , pred .

Example

Run this code 
#include <experimental/algorithm>
#include <experimental/functional>
#include <iostream>
#include <string>
 
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::experimental::search(in.begin(), in.end(),
                  std::experimental::make_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 the first occurrence of a range of elements
(function template)
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