//Make sure it's number
bool is_number(const std::string &s) {
if (s.empty() || s.length() <= 0) {
return false;
}
int point = 0;
if(s.length() == 1) {
if(s[0] >'9' || s[0] < '0')
return false;
}
if(s.length()>1) {
if (s[0]!='.' && (s[0] >'9' || s[0] < '0')&&s[0]!='-' && s[0]!='+') {
return false;
}
if (s[0] == '.') {
++point;
}
if ((s[0] == '+' || s[0] == '-') && (s[1] >'9' || s[1] < '0')) { return false; }
for (size_t i=1; i< s.length(); ++i) {
if (s[i]!='.' && (s[i] >'9' || s[i] < '0')) {
return false;
}
if (s[i] == '.') {
++point;
}
}
}
if (point > 1) {
return false;
}
return true;
}
