std::max_element
From Cppreference
| Defined in header <algorithm>
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| template< class ForwardIterator >
ForwardIterator max_element( ForwardIterator first, ForwardIterator last ); |
(1) | |
| template< class ForwardIterator, class Compare >
ForwardIterator max_element( ForwardIterator first, ForwardIterator last, |
(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.
Contents |
[edit] Parameters
| first, last | - | forward iterators defining the range to examine | |||||||||
| 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 const &, but the function must not modify the objects passed to it. |
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[edit] Return value
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.
[edit] Complexity
Exactly max(N-1,0) comparisons, where N = std::distance(first, last).
[edit] Equivalent function
| First version |
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template<class ForwardIterator> ForwardIterator max_element(ForwardIterator first, ForwardIterator last) { if (first == last) { return last; } ForwardIterator largest = first; ++first; for (; first != last; ++first) { if (*largest < *first) { largest = first; } } return largest; } |
| Second version |
template<class ForwardIterator, class Compare> ForwardIterator max_element(ForwardIterator first, ForwardIterator last, Compare comp) { if (first == last) { return last; } ForwardIterator largest = first; ++first; for (; first != last; ++first) { if (comp(*largest, *first)) { largest = first; } } return largest; } |
[edit] Example
#include <algorithm> #include <iostream> #include <vector> int main() { int data[] = { 3, 1, 4, 1, 5, 9 }; std::vector<int> v(data, data+6); std::vector<int>::iterator result = std::max_element(v.begin(), v.end()); std::cout << "max element at: " << std::distance(v.begin(), result); }
Output:
max element at: 5
[edit] See also
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returns the smallest element in a range (function template) |
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returns the smallest and the largest element in a range (function template) |
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returns the larger of two elements (function template) |
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