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std::max_element

From cppreference.com
 
 
 
Defined in header <algorithm>
template< class ForwardIterator >
ForwardIterator max_element( ForwardIterator first, ForwardIterator last );
(1)
template< class ForwardIterator, class Compare >

ForwardIterator max_element( ForwardIterator first, ForwardIterator 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.

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:

bool cmp(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 an object of type ForwardIterator can be dereferenced and then implicitly converted to both of them. ​

[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] Possible implementation

[edit] Example

#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

[edit] See also

returns the smallest element in a range
(function template) [edit]
returns the smallest and the largest element in a range
(function template) [edit]
returns the larger of two elements
(function template) [edit]