std::upper_bound

definiert in Header `<algorithm>`

`template< class ForwardIt, class T > ForwardIt upper_bound( ForwardIt first, ForwardIt last, const T& value );`	(1)

`template< class ForwardIt, class T, class Compare > ForwardIt upper_bound( ForwardIt first, ForwardIt last, const T& value, Compare comp );`	(2)

Gibt den Iterator auf das erste Element im Bereich [first, last) das größer als value ist zurück. Die erste Version verwendet operator< um die Elemente zu vergleichen, die zweite Version die gegebene Vergleichsfunktion comp.

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.
value	-	Wert auf die Elemente zu vergleichen Original: value to compare the elements to The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
comp	-	comparison function which returns `true` if the first argument is less than the second. The signature of the comparison function should be equivalent to the following: `bool cmp(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 `T` can be implicitly converted to `Type1`. The type `Type2` must be such that an object of type `ForwardIt` can be dereferenced and then implicitly converted to `Type2`.
Type requirements
- `ForwardIt` must meet the requirements of `ForwardIterator`.

Rückgabewert

Iterator, der auf dem ersten Element, die größer ist' als value oder last wenn ein solches Element gefunden wird .
Original:
iterator pointing to the first element that is greater than value, or last if no such element is found.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Mögliche Implementierung

First version

template<class ForwardIt, class T>
ForwardIt upper_bound(ForwardIt first, ForwardIt last,
                            const T& value)
{
    ForwardIt it;
    std::iterator_traits<ForwardIt>::distance_type count, step;
    count = std::distance(first,last);

    while (count > 0) {
        it = first; 
        step = count / 2; 
        std::advance(it, step);
        if (!(value < *it)) {
            first = ++it;
            count -= step + 1;
        } else count = step;
    }
    return first;
}

Second version

template<class ForwardIt, class T, class Compare>
ForwardIt upper_bound(ForwardIt first, ForwardIt last,
                            const T& value, Compare comp)
{
    ForwardIt it;
    std::iterator_traits<ForwardIt>::distance_type count, step;
    count = std::distance(first,last);

    while (count > 0) {
        it = first; 
        step = count / 2;
        std::advance(it, step);
        if (!comp(value, *it)),
            first = ++it;
            count -= step + 1
        } else count = step;
    }
    return first;
}

Beispiel

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>

int main()
{
    std::vector<int> data = { 1, 1, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 6 };
    
    auto lower = std::lower_bound(data.begin(), data.end(), 4);
    auto upper = std::upper_bound(data.begin(), data.end(), 4);
    
    std::copy(lower, upper, std::ostream_iterator<int>(std::cout, " "));
}

Output:

4 4 4

Komplexität

logarithmischen im Abstand zwischen first und last

Siehe auch


equal_range	Bandbreite der Rendite von Elementen übereinstimmenden eine bestimmte Taste Original: returns range of elements matching a specific key 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]

lower_bound	liefert einen Iterator auf das erste Element nicht weniger als der angegebene Wert Original: returns an iterator to the first element not less than the given value 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]

Sprache
Concepts
Utilities-Bibliothek
Strings Bibliothek
Container-Bibliothek
Algorithmen-Bibliothek
Iteratoren Bibliothek
Numerik-Bibliothek
Input / Output-Bibliothek
Lokalisierungen Bibliothek
Reguläre Ausdrücke Bibliothek (C++11)
Atomare Operationen Bibliothek (C++11)
Thread Support-Bibliothek (C++11)

cppreference.com

Suche

Namensräume

Varianten

Ansichten

Aktionen