Сигал, задача №4, 09.2009

typedef set<int> result_type;

template <typename T, typename F>
T ConvertTo(F f)
{
    std::stringstream st;
    st << f;
    T t;
    st >> t;
    return t;
}

result_type parse(const string &rsSource)
{
    result_type xResult;
    string::size_type i = 0, iSourceSize = rsSource.size();

    int iRangeBegin;

    enum
    {
        wmSingle,
        wmRange
    } eWorkMode = wmSingle;

    while (i < uiSourceSize)
    {
        string::size_type j = i;

        for ( ; (i < uiSourceSize) && (rsSource[i] >= '0') && (rsSource[i] <= '9') ; i++ ) {} // this is intent

        if (i == uiSourceSize || rsSource[i] == ',')
        {
            if (eWorkMode == wmSingle)
                xResult.insert(ConvertTo<int>(rsSource.substr(j, i-j)));
            else
            {
                int iRangeEnd = ConvertTo<int>(rsSource.substr(j, i-j));

                for (int n = iRangeBegin; n <= iRangeEnd; n++)
                    xResult.insert(n);
            }
        }
        else if (rsSource[i] == '-')
        {
            eWorkMode = wmRange;
            iRangeBegin = ConvertTo<int>(rsSource.substr(j, i-j));
        }
    }

    if (eWorkMode == wmRange)
        return result_type(); // what shit is it?!
}