// ss should represent a simple sum like 2+5*I
std::string ss(s);
// make it safe by adding explicit sign
- if (ss.at(0) != '+' && ss.at(0) != '-')
+ if (ss.at(0) != '+' && ss.at(0) != '-' && ss.at(0) != '#')
ss = '+' + ss;
std::string::size_type delim;
do {