mz04-2

template<typename T1, typename T2 = typename T1::value_type>
T2
process(const T1 &container, int SUM_NUMBER = 3)
{
    typename T1::const_iterator end = container.end();
    int number = SUM_NUMBER;
    T2 sum = T2();

    while (end != container.begin() && number-- > 0) {
        --end;
        sum += *end;
    }

    return sum;
}