std::find_end — cppreference.com

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Déclaré dans l'en-tête `<algorithm>`
`template< class ForwardIt1, class ForwardIt2 > ForwardIt1 find_end( ForwardIt1 first, ForwardIt1 last, ForwardIt2 s_first, ForwardIt2 s_last );`	(1)
`template< class ForwardIt1, class ForwardIt2, class BinaryPredicate > ForwardIt1 find_end( ForwardIt1 first, ForwardIt1 last, ForwardIt2 s_first, ForwardIt2 s_last, BinaryPredicate p );`	(2)

Recherches pour la sous-séquence de la dernière [s_first, s_last) éléments dans le [first, last) gamme. La première version utilise operator== de comparer les éléments, la deuxième version utilise le prédicat binaire donné p .

Original:

Searches for the last subsequence of elements [s_first, s_last) in the range [first, last). The first version uses operator== to compare the elements, the second version uses the given binary predicate p.

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Paramètres

first, last	-	l'éventail des éléments à examiner 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.
s_first, s_last	-	l'éventail des éléments à rechercher Original: the range of 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 types `Type1` and `Type2` must be such that objects of types `ForwardIt1` and `ForwardIt2` can be dereferenced and then implicitly converted to `Type1` and `Type2` respectively.
Type requirements
-`ForwardIt1` must meet the requirements of `ForwardIterator`.
-`ForwardIt2` must meet the requirements of `ForwardIterator`.

Retourne la valeur

Itérateur au début de séquence [s_first, s_last) dernière gamme [first, last) .

Original:

Iterator to the beginning of last subsequence [s_first, s_last) in range [first, last).

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Si aucune séquence n'est trouvée, last est retourné. (avant C++11)

Original:

If no such subsequence is found, last is returned. (avant C++11)

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Si [s_first, s_last) est vide ou si aucune séquence n'est trouvée, last est retourné. (depuis C++11)

Original:

If [s_first, s_last) is empty or if no such subsequence is found, last is returned. (depuis C++11)

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Complexité

Est-ce que la plupart des comparaisons à S*(N-S+1) où S = distance(s_first, s_last) et N = distance(first, last) .

Original:

Does at most S*(N-S+1) comparisons where S = distance(s_first, s_last) and N = distance(first, last).

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Mise en œuvre possible

First version
template<class ForwardIt1, class ForwardIt2> ForwardIt1 find_end(ForwardIt1 first, ForwardIt1 last, ForwardIt2 s_first, ForwardIt2 s_last) { if (s_first == s_last) return last; ForwardIt1 result = last; while (1) { ForwardIt1 new_result = std::search(first, last, s_first, s_last); if (new_result == last) { return result; } else { result = new_result; first = result; ++first; } } return result; }
Second version
template<class ForwardIt1, class ForwardIt2, class BinaryPredicate> ForwardIt1 find_end(ForwardIt1 first, ForwardIt1 last, ForwardIt2 s_first, ForwardIt2 s_last, BinaryPredicate p) { if (s_first == s_last) return last; ForwardIt1 result = last; while (1) { ForwardIt1 new_result = std::search(first, last, s_first, s_last, p); if (new_result == last) { return result; } else { result = new_result; first = result; ++first; } } return result; }

First version

template<class ForwardIt1, class ForwardIt2>
ForwardIt1 find_end(ForwardIt1 first, ForwardIt1 last,
                    ForwardIt2 s_first, ForwardIt2 s_last)
{
    if (s_first == s_last)
        return last;
    ForwardIt1 result = last;
    while (1) {
        ForwardIt1 new_result = std::search(first, last, s_first, s_last);
        if (new_result == last) {
            return result;
        } else {
            result = new_result;
            first = result;
            ++first;
        }
    }
    return result;
}

Second version

template<class ForwardIt1, class ForwardIt2, class BinaryPredicate>
ForwardIt1 find_end(ForwardIt1 first, ForwardIt1 last,
                    ForwardIt2 s_first, ForwardIt2 s_last,
                    BinaryPredicate p)
{
    if (s_first == s_last)
        return last;
    ForwardIt1 result = last;
    while (1) {
        ForwardIt1 new_result = std::search(first, last, s_first, s_last, p);
        if (new_result == last) {
            return result;
        } else {
            result = new_result;
            first = result;
            ++first;
        }
    }
    return result;
}

Exemple

Le code suivant utilise find_end() à la recherche de deux séquences différentes de numéros .

Original:

The following code uses find_end() to search for two different sequences of numbers.

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

int main()
{
    std::vector<int> v{1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4};
    std::vector<int>::iterator result;
 
    std::vector<int> t1{1, 2, 3};

    result = std::find_end(v.begin(), v.end(), t1.begin(), t1.end());
    if (result == v.end()) {
        std::cout << "subsequence not found\n";
    } else {
        std::cout << "last subsequence is at: "
                  << std::distance(v.begin(), result) << "\n";
    }

    std::vector<int> t2{4, 5, 6};
    result = std::find_end(v.begin(), v.end(), t2.begin(), t2.end());
    if (result == v.end()) {
        std::cout << "subsequence not found\n";
    } else {
        std::cout << "last subsequence is at: " 
                  << std::distance(v.begin(), result) << "\n";
    }
}

Résultat :

last subsequence is at: 8
subsequence not found

Voir aussi


adjacent_find	trouve deux identiques (ou une autre relation) des éléments adjacents les uns aux autres Original: finds two identical (or some other relationship) items adjacent to each other 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]

find find_if find_if_not (C++11)	trouve le premier élément répondant à des critères spécifiques Original: finds the first element satisfying specific criteria 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]

find_first_of	searches for any one of a set of elements (fonction générique) [edit]

search_n	Recherches pour un nombre de copies consécutives d'un élément dans une gamme Original: searches for a number consecutive copies of an element in a range 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]