////////////////////////////////////////////////////////////////// //////**************CHALLENGE: Palindrome Numbers //////****************Author: Petros Simidyan ////***************** #include //recursive function, that returns the number of digits the given integer constexpr int numberOfDigits(const int& input, const int& number = 0) { if (input < 10) return number+1; return numberOfDigits(input/10, number+1); } //function counts the "base" in power of "power" //if base is not given, it is equal to 10, output is help variable constexpr int power(const int& pow, const int& base = 10, const int& output=1) { if (pow < 1) return output; return power(pow -1, base, output*base); } //function returns true if the given number is palindrom constexpr bool isPalindromNumber(const int& input) { if (input < 10) return true; int pow = numberOfDigits(input); int firstDigit = input / power(pow-1); int lastDigit = input%10; if (firstDigit != lastDigit) return false; else return isPalindromNumber((input%power(pow - 2) )/ 10); } inline void printAllPalindrom(const int& max) { std::cout << "Here are all palindrom numbers between 11 and " << max << std::endl; for (int i = 11; i <= max; i++) if (isPalindromNumber(i)) std::cout << i << ", "; std:: cout <