Задача по строкам

[pproger]

2Croessmah

double get_sum(const string &str)
{
    double ret = 0.0;
    stringstream ss(str);

    while (ss) {
        ret += accumulate(istream_iterator<double>(ss), istream_iterator<double>(), 0.0);
        ss.clear();
        ss.get();
    }

    return ret;
}