Espaces de noms
Variantes
Affichages
Actions

std::lower_bound

De cppreference.com
< cpp‎ | algorithm

 
 
Bibliothèque d'algorithmes
Fonctions
Original:
Functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Non-modification de la séquence des opérations
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.
Modification de la séquence des opérations
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.
Des opérations de partitionnement
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.
Opérations de tri (sur les gammes triés)
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.
is_sorted (C++11)
is_sorted_until (C++11)
sort
Opérations binaires de recherche (sur les gammes triés)
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.
lower_bound
upper_bound
Définir les opérations (sur les gammes triés)
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.
Opérations Heap
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 de fonctionnement
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.
Opérations numériques
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.
Bibliothèque C
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.
 
Defined in header <algorithm>
template< class ForwardIt, class T >
ForwardIt lower_bound( ForwardIt first, ForwardIt last, const T& value );
(1)
template< class ForwardIt, class T, class Compare >
ForwardIt lower_bound( ForwardIt first, ForwardIt last, const T& value, Compare comp );
(2)
Retourne un itérateur pointant sur le premier élément dans la gamme [first, last) qui n'est pas' moins que value. La première version utilise operator< de comparer les éléments, la deuxième version utilise la fonction de comparaison donnée comp .
Original:
Returns an iterator pointing to the first element in the range [first, last) that is not less than value. 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.

Sommaire

[modifier] Paramètres

first, last -
itérateurs définissant la plage d'examiner
Original:
iterators defining the range 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 -
valeur à comparer les éléments d'
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 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.

[modifier] Retourne la valeur

Itérateur pointant sur le premier élément qui n'est pas moins de value ou last si aucun élément correspondant n'est trouvé .
Original:
Iterator pointing to the first element that is not less 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.

[modifier] Complexité

Logarithmique de la distance entre first et 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.

[modifier] Mise en œuvre possible

First version
template<class ForwardIt, class T>
ForwardIt lower_bound(ForwardIt first, ForwardIt last, const T& value)
{
    ForwardIt it;
    std::iterator_traits<ForwardIt>::difference_type count, step;
    count = std::distance(first, last);
 
    while (count > 0) {
        it = first; 
        step = count / 2; 
        std::advance(it, step);
        if (*it < value) {
            first = ++it; 
            count -= step + 1; 
        } else count = step;
    }
    return first;
}
Second version
template<class ForwardIt, class T, class Compare>
ForwardIt lower_bound(ForwardIt first, ForwardIt last, const T& value, Compare comp)
{
    ForwardIt it;
    std::iterator_traits<ForwardIt>::difference_type count, step;
    count = std::distance(first,last);
 
    while (count > 0) {
        it = first;
        step = count / 2;
        std::advance(it, step);
        if (comp(*it, value)),
            first = ++it;
            count -= step + 1;
        } else count = step;
    }
    return first;
}

[modifier] Exemple

#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, " "));
}

Résultat :

4 4 4

[modifier] Voir aussi

rendements varient d'éléments correspondant à une clé spécifique
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.

(fonction générique) [edit]
retourne un itérateur sur le premier élément' plus grande qu'une certaine valeur
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.

(fonction générique) [edit]