std::max_element
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<metanoindex/>
<tbody> </tbody>| Elemento definito nell'header <algorithm>
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template< class ForwardIt > ForwardIt max_element( ForwardIt first, ForwardIt last ); |
(1) | |
template< class ForwardIt, class Compare > ForwardIt max_element( ForwardIt first, ForwardIt last, Compare comp ); |
(2) | |
Finds the greatest element in the range [first, last). The first version uses operator< to compare the values, the second version uses the given comparison function comp.
Parametri
| first, last | - | iteratori forward che definiscono l'intervallo di esaminare
Original: forward 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. |
| cmp | - | comparison function which returns true if if *a is less than *b. The signature of the comparison function should be equivalent to the following:
The signature does not need to have |
| Type requirements | ||
-ForwardIt must meet the requirements of ForwardIterator.
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Valore di ritorno
Iterator to the greatest element in the range [first, last). If several elements in the range are equivalent to the greatest element, returns the iterator to the first such element. Returns last if the range is empty.
Complessità
N = std::distance(first, last) dove.N = std::distance(first, last).You can help to correct and verify the translation. Click here for instructions.
Possibile implementazione
| First version |
|---|
template<class ForwardIt>
ForwardIt max_element(ForwardIt first, ForwardIt last)
{
if (first == last) {
return last;
}
ForwardIt largest = first;
++first;
for (; first != last; ++first) {
if (*largest < *first) {
largest = first;
}
}
return largest;
}
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| Second version |
template<class ForwardIt, class Compare>
ForwardIt max_element(ForwardIt first, ForwardIt last,
Compare comp)
{
if (first == last) {
return last;
}
ForwardIt largest = first;
++first;
for (; first != last; ++first) {
if (comp(*largest, *first)) {
largest = first;
}
}
return largest;
}
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Esempio
#include <algorithm>
#include <iostream>
#include <vector>
#include <cmath>
static bool abs_compare(int a, int b)
{
return (std::abs(a) < std::abs(b));
}
int main()
{
std::vector<int> v{ 3, 1, -14, 1, 5, 9 };
std::vector<int>::iterator result;
result = std::max_element(v.begin(), v.end());
std::cout << "max element at: " << std::distance(v.begin(), result) << '\n';
result = std::max_element(v.begin(), v.end(), abs_compare);
std::cout << "max element (absolute) at: " << std::distance(v.begin(), result);
}
Output:
max element at: 5
max element (absolute) at: 2
Vedi anche
restituisce l'elemento più piccolo in un intervallo Original: returns the smallest 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. (funzione di modello) | |
(C++11) |
restituisce l'elemento più piccolo e il più grande in un intervallo Original: returns the smallest and the largest 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. (funzione di modello) |
restituisce il più grande dei due elementi Original: returns the larger of two elements 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) | |