Книга: Standard Template Library Programmer

min_element

min_element

Category: algorithms

Component type: function

Min_element is an overloaded name; there are actually two min_element functions.

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

Min_element finds the smallest 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 smaller than *i. The return value is last if and only if [first, last) is an empty range.

The two versions of min_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 min_element returns the first iterator i in [first, last) such that, for every iterator j in [first, last), *j < *i is false. The second version returns the first iterator i in [first, last) such that, for every iterator j in [first, last), comp(*j, *i) 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 = min_element(L.begin(), L.end());
 cout << "The smallest element is " << *it << endl;
}

min, max  max_element, LessThan Comparable, sort, nth_element

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