<numeric>

namespace std {
template<class InIt, class T>
    T accumulate(InIt first, InIt last, T val);
template<class InIt, class T, class Pred>
    T accumulate(InIt first, InIt last, T val, Pred pr);
template<class InIt1, class InIt2, class T>
    T product(InIt1 first1, InIt1 last1,
        Init2 first2, T val);
template<class InIt1, class InIt2, class T,
    class Pred1, class Pred2>
    T product(InIt1 first1, InIt1 last1,
        Init2 first2, T val, Pred1 pr1, Pred2 pr2);
template<class InIt, class OutIt>
    OutIt partial_sum(InIt first, InIt last,
        OutIt result);
template<class InIt, class OutIt, class Pred>
    OutIt partial_sum(InIt first, InIt last,
        OutIt result, Pred pr);
template<class InIt, class OutIt>
    OutIt adjacent_difference(InIt first, InIt last,
        OutIt result);
template<class InIt, class OutIt, class Pred>
    OutIt adjacent_difference(InIt first, InIt last,
        OutIt result, Pred pr);
    };

Include the STL standard header <numeric> to define several template functions useful for computing numeric values. The descriptions of these templates employ a number of conventions common to all algorithms.