std::find_first_of
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<metanoindex/>
<tbody> </tbody>| Elemento definito nell'header <algorithm>
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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) | (fino al c++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) | (fino al c++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. The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Parametri
| first, last | - | la gamma di elementi da esaminare
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 | - | la gamma di elementi da cercare
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:
The signature does not need to have |
| Type requirements | ||
-InputIt must meet the requirements of InputIterator.
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-ForwardIt1 must meet the requirements of ForwardIterator.
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-ForwardIt2 must meet the requirements of ForwardIterator.
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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.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
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).The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
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;
}
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| 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;
}
|
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:
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
#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
Vedi anche
(C++11) |
trova il primo elemento che soddisfi i criteri specifici 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. (funzione di modello) |
