std::max_element

default (1)	template <class ForwardIterator> ForwardIterator max_element (ForwardIterator first, ForwardIterator last);
custom (2)	template <class ForwardIterator, class Compare> ForwardIterator max_element (ForwardIterator first, ForwardIterator last, Compare comp);

default (1)

template <class ForwardIterator>  ForwardIterator max_element (ForwardIterator first, ForwardIterator last);

custom (2)

template <class ForwardIterator, class Compare>  ForwardIterator max_element (ForwardIterator first, ForwardIterator last,                               Compare comp);

Return largest element in range

Returns an iterator pointing to the element with the largest value in the range [first,last).

The comparisons are performed using either operator< for the first version, or comp for the second; An element is the largest if no other element does not compare less than it. If more than one element fulfills this condition, the iterator returned points to the first of such elements.

The behavior of this function template is equivalent to:

template <class ForwardIterator>
  ForwardIterator max_element ( ForwardIterator first, ForwardIterator last )
{
  if (first==last) return last;
  ForwardIterator largest = first;

  while (++first!=last)
    if (*largest<*first)    // or: if (comp(*largest,*first)) for version (2)
      largest=first;
  return largest;
}

Parameters

first, last: Input iterators to the initial and final positions of the sequence to compare. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
comp: Binary function that accepts two elements in the range as arguments, and returns a value convertible to bool. The value returned indicates whether the element passed as first argument is considered less than the second.
The function shall not modify any of its arguments.
This can either be a function pointer or a function object.

Return value

An iterator to largest value in the range, or last if the range is empty.

Example

// min_element/max_element example
#include <iostream>     // std::cout
#include <algorithm>    // std::min_element, std::max_element

bool myfn(int i, int j) { return i<j; }

struct myclass {
  bool operator() (int i,int j) { return i<j; }
} myobj;

int main () {
  int myints[] = {3,7,2,5,6,4,9};

  // using default comparison:
  std::cout << "The smallest element is " << *std::min_element(myints,myints+7) << '\n';
  std::cout << "The largest element is "  << *std::max_element(myints,myints+7) << '\n';

  // using function myfn as comp:
  std::cout << "The smallest element is " << *std::min_element(myints,myints+7,myfn) << '\n';
  std::cout << "The largest element is "  << *std::max_element(myints,myints+7,myfn) << '\n';

  // using object myobj as comp:
  std::cout << "The smallest element is " << *std::min_element(myints,myints+7,myobj) << '\n';
  std::cout << "The largest element is "  << *std::max_element(myints,myints+7,myobj) << '\n';

  return 0;
}

Output:

The smallest element is 2
The largest element is 9
The smallest element is 2
The largest element is 9
The smallest element is 2
The largest element is 9

Complexity

Linear in one less than the number of elements compared.

Data races

The objects in the range [first,last) are accessed.

Exceptions

Throws if any comparison throws.
Note that invalid arguments cause undefined behavior.