/* Instructions for use Enter an IP address when prompted example inputs 192.168.1.1 10.10.s.10 1025.35 10.10.10.10.10 */ #include #include #include #include // splits a string based on provided delimiter // new split from: // https://www.safaribooksonline.com/library/view/c-cookbook/0596007612/ch04s07.html // documented / researched (it is better than my attempt, but I wasn't far off :D ) std::vector split(std::string stringToSplit, std::string delimiter) { std::vector retValue; std::string field; //http://www.cplusplus.com/reference/cstring/size_t/ // size_t: Alias of one of the fundamental unsigned integer types // Able to represent the size of any object in bytes size_t currentPos = 0; // http://www.cplusplus.com/reference/string/string/find/ // finds the first occurance of the specified character, when pos is specified // it only searches at or after the position (currentPos) size_t index = stringToSplit.find(delimiter, currentPos); //http://www.cplusplus.com/reference/string/string/npos/ //npos is a static member constant value with the greatest possible value for an element of type size_t. while (index != std::string::npos) { // http://www.cplusplus.com/reference/string/string/substr/ // substr - returns a new string object with the value that is a substring of the object // The substring is the portion that starts at character position currentPos and spans the length // of index - currentPos retValue.push_back(stringToSplit.substr(currentPos, index - currentPos)); currentPos = ++index; // move index to past the current delimiter index = stringToSplit.find(delimiter, currentPos); // find the next delimiter //push back the last field if (index == std::string::npos) { retValue.push_back(stringToSplit.substr(currentPos, stringToSplit.length())); } } /* Old split code for (auto& character : stringToSplit) { //is the character the delimiter if (character == '.') { retValue.push_back(field); field = ""; } else { field += character; } } //pushback last field if (field != "") retValue.push_back(field); */ return retValue; } // converts string number into integer // e.g "256" -> 256 int stringToInt(std::string stringInt) { int retVal{ 0 }; for (auto& character : stringInt) { //increase return value by power of 10 retVal *= 10; //convert character to integer by removing char('0') (ascii value 48) and add it to return value retVal += character - '0'; } return retVal; } bool isValidIP(std::string ip) { //split string at full stops. std::vector octets{ split(ip,".") }; //check number of splits, should be 4 if (octets.size() != 4) { return false; } int octetAsInt; for (auto& octet : octets) { //convert each character into integer //check to see if octet contains letters // (they will convert to two digits integers) if (octet == "" || octet.length() > 3) return false; for (auto character : octet) { //check to see if character is a number if(!std::isdigit(character)) return false; } // check octet sits between range octetAsInt = stringToInt(octet); if (octetAsInt < 0 || octetAsInt > 255) return false; } return true; } int main() { std::string ipAddr; std::cin >> ipAddr; std::cout << "You entered: " << ipAddr << std::endl; if (isValidIP(ipAddr)) { std::cout << "Valid IP address\n"; } else { std::cout << "Invalid IP address\n"; } std::cin >> ipAddr; return 0; }

IsThatAnIpAddress