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

From cppreference.com
< cpp‎ | experimental

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`.

### [edit] 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)

### [edit] 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);

### [edit] Parameters

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

### [edit] Return value

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

### [edit] Example

Run this code

    #include <iostream>
    #include <string>
    #include <experimental/algorithm>
    #include <experimental/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::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

### [edit] See also

search | searches for a range of elements (function template) [edit]

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