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std::find_first_of

Da cppreference.com.
< cpp‎ | algorithm

 
 
Algoritmo libreria
Funzioni
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Functions
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Non modifica le operazioni di sequenza
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Non-modifying sequence operations
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Modifica delle operazioni di sequenza
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Modifying sequence operations
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Partizionamento operazioni
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Partitioning operations
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Ordinamento delle operazioni (su intervalli ordinati)
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Sorting operations (on sorted ranges)
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Binarie (le operazioni di ricerca sui campi ordinati)
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Binary search operations (on sorted ranges)
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Impostare le operazioni (su intervalli ordinati)
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Set operations (on sorted ranges)
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Heap operazioni
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Heap operations
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Minimo / massimo le operazioni
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Minimum/maximum operations
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Operazioni numeriche
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Numeric operations
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Libreria C
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C library
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Defined in header <algorithm>
template< class ForwardIt1, class ForwardIt2 >

ForwardIt1 find_first_of( ForwardIt1 first, ForwardIt1 last,
                          ForwardIt2 s_first, ForwardIt2 s_last );
template< class InputIt, class ForwardIt >
InputIt find_first_of( InputIt first, InputIt last,

                       ForwardIt s_first, ForwardIt s_last );
(1) (C fino + 11)


(dal C++11)
template< class ForwardIt1, class ForwardIt2, class BinaryPredicate >

ForwardIt1 find_first_of( ForwardIt1 first, ForwardIt1 last,
                          ForwardIt2 s_first, ForwardIt2 s_last, BinaryPredicate p );
template< class InputIt, class ForwardIt, class BinaryPredicate >
InputIt find_first_of( InputIt first, InputIt last,

                       ForwardIt s_first, ForwardIt s_last, BinaryPredicate p );
(2) (C fino + 11)


(dal C++11)
Cerca nella [first, last) gamma per ogni elemento della [s_first, s_last) gamma. La prima versione utilizza operator== di confrontare gli elementi, la seconda versione utilizza il predicato binario dato p.
Original:
Searches the range [first, last) for any of the elements in the range [s_first, s_last). The first version uses operator== to compare the elements, the second version uses the given binary predicate p.
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Indice

[modifica] Parametri

first, last -
la gamma di elementi da esaminare
Original:
the range of elements to examine
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s_first, s_last -
la gamma di elementi da cercare
Original:
the range of elements to search for
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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
-
InputIt must meet the requirements of InputIterator.
-
ForwardIt1 must meet the requirements of ForwardIterator.
-
ForwardIt2 must meet the requirements of ForwardIterator.

[modifica] Valore di ritorno

Iteratore al primo elemento nella [first, last) gamma che è uguale a un elemento dal [s_first; s_last) gamma. Se tale elemento non viene trovato, viene restituito last.
Original:
Iterator to the first element in the range [first, last) that is equal to an element from the range [s_first; s_last). If no such element is found, last is returned.
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[modifica] Complessità

Fa a confronto la maggior parte (S*N) dove S = distance(s_first, s_last) e N = distance(first, last).
Original:
Does at most (S*N) comparisons where S = distance(s_first, s_last) and N = distance(first, last).
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[modifica] Possibile implementazione

First version
template<class InputIt, class ForwardIt>
InputIt find_first_of(InputIt first, InputIt last,
                      ForwardIt s_first, ForwardIt s_last)
{
    for (; first != last; ++first) {
        for (ForwardIt it = s_first; it != s_last; ++it) {
            if (*first == *it) {
                return first;
            }
        }
    }
    return last;
}
Second version
template<class InputIt, class ForwardIt, class BinaryPredicate>
InputIt find_first_of(InputIt first, InputIt last,
                      ForwardIt s_first, ForwardIt s_last,
                      BinaryPredicate p)
{
    for (; first != last; ++first) {
        for (ForwardIt it = s_first; it != s_last; ++it) {
            if (p(*first, *it)) {
                return first;
            }
        }
    }
    return last;
}

[modifica] Esempio

Le ricerche di codice seguenti per uno qualsiasi dei numeri interi specificati in un vettore di interi:
Original:
The following code searches for any of specified integers in a vector of integers:
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#include <algorithm>
#include <iostream>
#include <vector>
 
int main()
{
    std::vector<int> v{0, 2, 3, 25, 5};
    std::vector<int> t{3, 19, 10, 2};
 
    auto result = std::find_first_of(v.begin(), v.end(), t.begin(), t.end());
 
    if (result == v.end()) {
        std::cout << "no elements of v were equal to 3, 19, 10 or 2\n";
    } else {
        std::cout << "found a match at "
                  << std::distance(v.begin(), result) << "\n";
    }
 }

Output:

found a match at 1

[modifica] Vedi anche

trova il primo elemento che soddisfi i criteri specifici
Original:
finds the first element satisfying specific criteria
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(funzione di modello) [edit]