help

string strOut = "";

    strOut = to_string(static_cast<long long>(num));

    for(int i = 0; i < strOut.size() - 1; i++)
    {
        if((strOut.size() - (i+1)) % 3 == 0)
        {
            i++;
            strOut.insert(i, ",");
        }
    }

    if(*strOut.begin() == ',')
    {
        strOut.erase(0, 1);
    }

    strOut.insert(strOut.begin(), '$');

    return strOut;