Книга: Standard Template Library Programmer

max_element

max_element

Category: algorithms

Component type: function

Max_element is an overloaded name; there are actually two max_element functions.

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

Max_element finds the largest element in the range [first, last). It returns the first iterator i in [first, last) such that no other iterator in [first, last) points to a value greater than *i. The return value is last if and only if [first, last) is an empty range.

The two versions of max_element differ in how they define whether one element is less than another. The first version compares objects using operator<, and the second compares objects using a function object comp.

The first version of max_element returns the first iterator i in [first, last) such that, for every iterator j in [first, last), *i < *j is false. The second version returns the first iterator i in [first, last) such that, for every iterator j in [first, last), comp(*i, *j) is false.

Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.

For the first version:

• ForwardIterator is a model of Forward Iterator.

• ForwardIterator's value type is LessThan Comparable.

For the second version:

• ForwardIterator is a model of Forward Iterator.

• BinaryPredicate is a model of Binary Predicate.

• ForwardIterator's value type is convertible to BinaryPredicate's first argument type and second argument type.

• [first, last) is a valid range.

Linear. Zero comparisons if [first, last) is an empty range, otherwise exactly (last – first) – 1 comparisons.

int main() {
 list<int> L;
 generate_n(front_inserter(L), 1000, rand);
 list<int>::const_iterator it = max_element(L.begin(), L.end());
 cout << "The largest element is " << *it << endl;
}

min, max, min_element, LessThan Comparable, sort, nth_element

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