2.10进制整数转16进制字符串

string DecIntToHexStr(long long num)
    {
        string str;
            long long Temp = num / 16;
            int left = num % 16;

            if(Temp > 0)
            {
                str += DecIntToHexStr(Temp);
            }

            if(left < 10)
            {
                str += (left + '0');
            }
            else
            {
                str += ('A' + left - 10);
            }

            return str;
    }