default_searcher Class
A default_searcher is a function object type for operations that search for a sequence specified in the object's constructor. The search is done within another sequence provided to the object's function call operator. The default_searcher invokes std::search to perform the search.
Syntax
template <class ForwardIterator, class BinaryPredicate = equal_to<>>
class default_searcher
{
default_searcher(
ForwardIterator pat_first,
ForwardIterator pat_last,
BinaryPredicate pred = BinaryPredicate());
template <class ForwardIterator2>
pair<ForwardIterator2, ForwardIterator2> operator()(
ForwardIterator2 first,
ForwardIterator2 last) const;
};
Members
| Member | Description |
|---|---|
| Constructor | |
| default_searcher | Constructs a searcher instance. |
| Operators | |
| operator() | Invokes the operation on the sequence. |
default_searcher constructor
Constructs a default_searcher function object by using the sequence to search for and an equality predicate.
default_searcher( // C++17
ForwardIterator pat_first,
ForwardIterator pat_last,
BinaryPredicate pred = BinaryPredicate());
constexpr default_searcher( // C++20
ForwardIterator pat_first,
ForwardIterator pat_last,
BinaryPredicate pred = BinaryPredicate());
Parameters
pat_first
The initial element of the sequence to search for.
pat_last
The end of the sequence to search for.
pred
The optional equality comparison predicate for sequence elements. If an equality comparison type isn't specified, the default is std::equal_to.
Remarks
Throws any exception thrown by the copy constructor of the BinaryPredicate or ForwardIterator types.
This class is new in C++17. C++20 made the constructor constexpr.
operator()
The call operator of the function operator. Searches within the argument sequence [first, last) for the sequence specified to the constructor.
template <class ForwardIterator2> // C++17
pair<ForwardIterator2, ForwardIterator2> operator()(
ForwardIterator2 first,
ForwardIterator2 last) const;
template <class ForwardIterator2> // C++20
constexpr pair<ForwardIterator2, ForwardIterator2> operator()(
ForwardIterator2 first,
ForwardIterator2 last) const;
Parameters
first
The initial element of the sequence to search within.
last
The end of the sequence to search within.
Remarks
Returns a pair of iterators. The initial iterator i is the effective result of:
std::search( first, last, pat_first, pat_last, pred ).
The second iterator of the pair is last if i* is last. Otherwise, it's the effective result of:
std::next( i, std::distance( pat_first, pat_last )).
This class is new in C++17. C++20 made the call operator constexpr.