Namensräume
Varianten
Aktionen

std::equal_range

Aus cppreference.com
< cpp‎ | algorithm

This page has been machine-translated from the English version of the wiki using Google Translate.

The translation may contain errors and awkward wording. Hover over text to see the original version. You can help to fix errors and improve the translation. For instructions click here.

Click here for the English version of this page

 
C++
 
Algorithm Bibliothek
Funktionen
Original:
Functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Nicht-modifizierende Sequenz Operationen
Original:
Non-modifying sequence operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Modifizierende Sequenz Operationen
Original:
Modifying sequence operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Partitionierungsoperationen
Original:
Partitioning operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Sortierung Operationen (auf sortierten Bereiche)
Original:
Sorting operations (on sorted ranges)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Binary Suchaktionen (auf sortierten Bereiche)
Original:
Binary search operations (on sorted ranges)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
binary_search
equal_range
Set-Operationen (auf sortierten Bereiche)
Original:
Set operations (on sorted ranges)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Heap-Operationen
Original:
Heap operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Minimum / Maximum Operationen
Original:
Minimum/maximum operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Numerische Operationen
Original:
Numeric operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
C-Bibliothek
Original:
C library
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
 
definiert in Header <algorithm>
template< class ForwardIt, class T >

std::pair<ForwardIt,ForwardIt>
    equal_range( ForwardIt first, ForwardIt last,

                 const T& value );
 (1)
template< class ForwardIt, class T, class Compare >

std::pair<ForwardIt,ForwardIt>
    equal_range( ForwardIt first, ForwardIt last,

                 const T& value, Compare comp );
 (2)

Gibt einen Bereich mit allen Elementen, die gleich value sind im Bereich [first, last), der bzgl. value aufgeteilt ist. Der Bereich wird durch zwei Iterationen, einer auf das erste Element, das nicht weniger' als value und ein anderer, der auf dem ersten Element' definiert ist größer als value. Mit lower_bound() .. - Der erste Iterator kann alternativ mit upper_bound(), die zweite erhalten werden.

Die erste Version verwendet operator< um die Elemente zu vergleichen, verwendet die zweite Version des gegebenen Vergleichsfunktion comp .
Original:
The first version uses operator< to compare the elements, the second version uses the given comparison function comp.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Inhaltsverzeichnis

[Bearbeiten] 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.

[Bearbeiten] Rückgabewert

std::pair enthaltend ein Paar von Iteratoren Definieren des gewünschten Bereichs, der erste auf das erste Element, das nicht weniger' als value und der zweite auf das erste Element' größer als value .
Original:
std::pair containing a pair of iterators defining the wanted range, the first pointing to the first element that is not less than value and the second pointing to the first element greater than value.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Wenn keine Elemente' nicht weniger als value sind, wird last als erstes Element zurückgegeben. Ähnlich, wenn es keine Elemente' größer als value, last wird als zweites Element zurückgegeben
Original:
If there are no elements not less than value, last is returned as the first element. Similarly if there are no elements greater than value, last is returned as the second element
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[Bearbeiten] Komplexität

Logarithmisch im Abstand zwischen first und last
Original:
Logarithmic in the distance between first and last
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[Bearbeiten] Mögliche Implementierung

First version 
template<class ForwardIt, class T 
std::pair<ForwardIt,ForwardIt> 
    equal_range(ForwardIt first, ForwardIt last,
                const T& value)
{
    return std::make_pair(std::lower_bound(first, last, value),
                          std::upper_bound(first, last, value));
}
Second version 
template<class ForwardIt, class T, class Compare>
std::pair<ForwardIt,ForwardIt> 
    equal_range(ForwardIt first, ForwardIt last,
                const T& value, Compare comp);
{
    return std::make_pair(std::lower_bound(first, last, value, comp),
                          std::upper_bound(first, last, value, comp));
}

[Bearbeiten] Beispiel

#include <algorithm>
#include <vector>
#include <iostream>
 
struct S
{
    int number;
    char name;
 
    S ( int number, char name  )
        : number ( number ), name ( name )
    {}
 
    // only the number is relevant with this comparison
    bool operator< ( const S& s ) const
    {
        return number < s.number;
    }
};
 
 
int main()
{
    std::vector<S> vec = { {1,'A'}, {2,'B'}, {2,'C'}, {2,'D'}, {3,'F'}, {4,'G'} };
 
    S value ( 2, '?' );
 
    auto p = std::equal_range(vec.begin(),vec.end(),value);
 
    for ( auto i = p.first; i != p.second; ++i )
        std::cout << i->name << ' ';
}

Output: 

B C D

[Bearbeiten] Siehe auch
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]
liefert einen Iterator auf das erste Element mehr als ein bestimmter Wert
Original:
returns an iterator to the first element greater than a certain 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]
bestimmt, ob ein Element vorhanden ist in einem gewissen Bereich
Original:
determines if an element exists 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]
Von „https://de.cppreference.com/mwiki/index.php?title=cpp/algorithm/equal_range&oldid=31713“