max_element()

Library:  Algorithms

Function

• Local Index
• Summary
• Synopsis
• Description
• Complexity
• Example
• See Also
• Standards Conformance

An algorithm that finds the maximum value in a range

#include <algorithm>

namespace std {
  template <class ForwardIterator>
  ForwardIterator
  max_element(ForwardIterator start, ForwardIterator finish);

  template <class ForwardIterator, class Compare>
  ForwardIterator
  max_element(ForwardIterator start, ForwardIterator finish,
              Compare comp);
}

The max_element() algorithm returns an iterator that denotes the maximum element in a sequence. If the sequence contains more than one copy of the element, the iterator points to its first occurrence. The optional argument comp defines a function object that can be used in place of operator<().

Algorithm max_element() returns the first iterator i in the range [start, finish) such that for any iterator j in the same range either of the following conditions hold:

!(*i < *j)

or

comp(*i, *j) == false.

Exactly max((finish - start) - 1, 0) applications of the corresponding comparisons are done for max_element().

//
//  max_elem.cpp
//

#include <algorithm>    // for max_element
#include <functional>   // for less
#include <iostream>     // for cout, endl
#include <vector>       // for vector


int main ()
{
    typedef std::vector<int, std::allocator<int> > Vector;
    typedef Vector::iterator                       Iterator;

    const Vector::value_type d1[] = { 1, 3, 5, 32, 64 };                
    // Set up vector.
    Vector v1(d1 + 0, d1 + sizeof d1 / sizeof *d1);  

    // Find the largest element in the vector.
    Iterator it1 = std::max_element (v1.begin(), v1.end());

    // Find the largest element in the range from
    // the beginning of the vector to the 2nd to last.
    Iterator it2 = std::max_element (v1.begin(), v1.end() - 1,
                                     std::less<int>());

    // Find the smallest element.
    Iterator it3 = std::min_element (v1.begin(), v1.end());

    // Find the smallest value in the range from
    // the beginning of the vector plus 1 to the end.
    Iterator it4 = std::min_element (v1.begin() + 1, v1.end(),
                                     std::less<int>());

    std::cout << *it1 << " " << *it2 << " "
              << *it3 << " " << *it4 << std::endl;

    return 0;
}


Program Output:

64 32 1 3

max(), min(), min_element()

ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 25.3.7