How do you validate that a string is a valid IPv4 address in C++?

Question

I don\'t need to validate that the IP address is reachable or anything like that. I just want to validate that the string is in dotted-quad (xxx.xxx.xxx.xxx) IPv4 format, w

Answer 1

vector &split(const string &s, char delim, vector &elems) {
    stringstream ss(s);
    string item;
    while(getline(ss, item, delim)) {
       elems.push_back(item);
    }
    return elems;
}

vector split(const string &s, char delim) {
   vector elems;
   return split(s, delim, elems);
}


bool isIPAddress(string  ipaddr){

    if (ipaddr.length()){
            vector _ip=split(ipaddr,'.');
            if (_ip.size()==4){
                    for (int i=0; i < 4; i++){
                            for (int j=0; j < _ip[i].length(); j++)
                                    if (!isdigit(_ip[i][j])) return false;
                            if ((atoi(_ip[i].c_str()) < 0) || (atoi(_ip[i].c_str()) > 255)) return false;
                    }
            return true;
            }
    }
    return false;
 }