std::search_n – cppreference.com

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definiert in Header `<algorithm>`

`template< class ForwardIt, class Size, class T > ForwardIt1 search_n( ForwardIt first, ForwardIt last, Size count, const T& value );`	(1)

`template< class ForwardIt, class Size, class T, class BinaryPredicate > ForwardIt1 search_n( ForwardIt first, ForwardIt last, Size count, const T& value, BinaryPredicate p );`	(2)

Searches der Bereich [first, last) für die erste Folge des Grafen identische Elemente, die jeweils gleich dem angegebenen Wert Wert. Die erste Version verwendet operator== um die Elemente zu vergleichen, verwendet die zweite Version des gegebenen binären Prädikats p .

Original:

Searches the range [first, last) for the first sequence of count identical elements, each equal to the given value value. The first version uses operator== to compare the elements, the second version uses the given binary predicate p.

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Parameter

first, last	-	das Spektrum der Elemente zu untersuchen Original: the range of elements to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
count	-	die Länge der Sequenz zu suchen Original: the length of the sequence to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
value	-	der Wert der Elemente, nach dem gesucht Original: the value of the elements to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
p	-	binary predicate which returns `true` if the elements should be treated as equal. The signature of the predicate function should be equivalent to the following: `bool pred(const Type1 &a, const Type2 &b);` The signature does not need to have `const &`, but the function must not modify the objects passed to it. The type `Type1` must be such that an object of type `ForwardIt` can be dereferenced and then implicitly converted to `Type1`. The type `Type2` must be such that an object of type `T` can be implicitly converted to `Type2`.
Type requirements
-`ForwardIt` must meet the requirements of `ForwardIterator`.

Rückgabewert

Iiterator an den Anfang des gefundenen Sequenz im Bereich [first, last). Wenn keine solche Sequenz gefunden wird, wird zurückgegeben last .

Original:

Iiterator to the beginning of the found sequence in the range [first, last). If no such sequence is found, last is returned.

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Komplexität

An den meisten last - first Anwendungen des Prädikats .

Original:

At most last - first applications of the predicate.

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Mögliche Implementierung

First version
template<class ForwardIt, class Size, class T> ForwardIt1 search_n(ForwardIt first, ForwardIt last, Size count, const T& value) { Size curr_count = 0; ForwardIt result, t_last = first; std::advance(t_last, std::distance(first, last) - count + 1); for (; first != t_last; first++) { curr_count = 0; result = first; while (*first == value) { curr_count++; if (curr_count == count) { return result; } ++first; } } return last; }
Second version
template<class ForwardIt, class Size, class T, class BinaryPredicate> ForwardIt1 search_n(ForwardIt first, ForwardIt last, Size count, const T& value, BinaryPredicate p) { Size curr_count = 0; ForwardIt result, t_last = first; std::advance(t_last, std::distance(first, last) - count + 1); for (; first != t_last; first++) { curr_count = 0; result = first; while (p(*first == value)) { curr_count++; if (curr_count == count) { return result; } ++first; } } return last; }

First version

template<class ForwardIt, class Size, class T>
ForwardIt1 search_n(ForwardIt first, ForwardIt last,
                          Size count, const T& value)
{
    Size curr_count = 0;
    ForwardIt result, t_last = first;
    std::advance(t_last, std::distance(first, last) - count + 1);
 
    for (; first != t_last; first++) {
        curr_count = 0;
        result = first;
        while (*first == value) {
            curr_count++;
            if (curr_count == count) {
                return result;
            }
            ++first;
        }
    }
    return last;
}

Second version

template<class ForwardIt, class Size, class T, class BinaryPredicate>
ForwardIt1 search_n(ForwardIt first, ForwardIt last,
                          Size count, const T& value, BinaryPredicate p)
{
    Size curr_count = 0;
    ForwardIt result, t_last = first;
    std::advance(t_last, std::distance(first, last) - count + 1);
 
    for (; first != t_last; first++) {
        curr_count = 0;
        result = first;
        while (p(*first == value)) {
            curr_count++;
            if (curr_count == count) {
                return result;
            }
            ++first;
        }
    }
    return last;
}

Beispiel

Siehe auch


find_end	findet die letzte Sequenz von Elementen in einem bestimmten Bereich Original: finds the last sequence of elements in a certain range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktions-Template) [edit]

find find_if find_if_not (C++11)	Findet das erste Elemente, welches bestimmte Kriterien erfüllt (Funktions-Template) [edit]

search	searches for a range of elements (Funktions-Template) [edit]