std::ranges::max_element

Since C++20

Header: <algorithm>

Finds the greatest element in the range [first,last).

# Declarations

Call signature

template< std::forward_iterator I, std::sentinel_for<I> S, class Proj = std::identity,
std::indirect_strict_weak_order<std::projected<I, Proj>> Comp = ranges::less >
constexpr I
max_element( I first, S last, Comp comp = {}, Proj proj = {} );

(since C++20)

template< ranges::forward_range R, class Proj = std::identity,
std::indirect_strict_weak_order<
std::projected<ranges::iterator_t<R>, Proj>> Comp = ranges::less >
constexpr ranges::borrowed_iterator_t<R>
max_element( R&& r, Comp comp = {}, Proj proj = {} );

(since C++20)

# Parameters

first, last: iterator-sentinel pair denoting the range to examine
r: the range to examine
comp: comparison to apply to the projected elements
proj: projection to apply to the elements

# 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 (i.e. if first == last).

# Example

#include <algorithm>
#include <cmath>
#include <iostream>
 
int main()
{
    namespace ranges = std::ranges;
 
    const auto v = {3, 1, -14, 1, 5, 9, -14, 9};
 
    auto result = ranges::max_element(v.begin(), v.end());
    std::cout << "Max element at pos " << ranges::distance(v.begin(), result) << '\n';
 
    auto abs_compare = [](int a, int b) { return std::abs(a) < std::abs(b); };
    result = ranges::max_element(v, abs_compare);
    std::cout << "Absolute max element at pos "
              << ranges::distance(v.begin(), result) << '\n';
}