//////////////////////////////////////////////////////////////////// ////////**************CHALLENGE:Kaprekar's Numbers ////////****************Author: Petros Simidyan //////***************** /*The idea is folowing: save in array of length 10 number occurrence of each digit in input integer. After that we use this array to arrange the digits in des und aus way. Example: Input: 4466 Counterarray: indices:0123456789 values: 0000202000 Input: 4567 Counterarray: indices:0123456789 values: 0000111100 Input: 2333 Counterarray: indices:0123456789 values: 0013000000 For arranging the given digit in des oreder we need to go throw the array starting with the last element, in other case with 0 index. */ #include #include #define MAX 10 #define CLEAR std::cin.clear(); std::cin.ignore(1000, '\n'); #define KAR 6174 //the function counts the number of digits of the given integer //for testing, that the given integer has only 4 digits inline int numOfDigit(const int& input, const int& digits = 0) { if (input == 0) return digits; return numOfDigit(input / 10, digits + 1); } //the function test the input has only one digit, e. g. 4444, 1111 inline bool contSameNum(const int& input, const int& lastDigit) { if (input < 10) return input == lastDigit; if (input % 10 == lastDigit) return contSameNum(input / 10, input % 10); return false; } inline bool contSameNum(const int& input) { return contSameNum(input, input % 10); } //initialising all elements of the //given array input of length len with 0 inline void initIntArr(int* input, const int& len = MAX) { for (int i = 0; i < MAX; i++) input[i] = 0; } //"mixes" the greatest value inline int mixMax(int* countArr) { int max = 0, i = MAX - 1, count = -1;; for (; i >= 0; i--) if (countArr[i] > 0) { count = countArr[i]; while (count-- > 0) max = 10 * max + i; } return max; } inline int mixMin(int* countArr) { int min= 0, i = 0, count =-1; for (; i < MAX; i++) if (countArr[i] > 0) { count = countArr[i]; while (count-- > 0) min = 10 * min + i; } return min; } //the function creates a counter array, //and initialises input, mixMax and mixMin inline void initMinMax(int& input, int& max, int& min) { int * countArr = new int[MAX]; initIntArr(countArr); int lastDigit = -1; while (input > 0) { lastDigit = input % 10; countArr[lastDigit]++; input /= 10; } max = mixMax(countArr); min = mixMin(countArr); input = max - min; delete[]countArr; } inline void printStep(const int& input, const int& max, const int& min) { std::cout << max << " - " << min << " = " << input << std::endl; } inline int printKaprekar(int input) { int max = 0, min = 0, steps = 7; while (steps-->0&&input != KAR) { initMinMax(input, max, min); printStep(input, max, min); } return input ; } int main() { int input = -1; while (true) { std::cout << "Please give an positiv four-digits integer number!" << std::endl; if (std::cin.peek() == '-') {//making sure, that ght input an positiv integer is std::cout << "The given integers should be positiv!" << std::endl; CLEAR } else { std::cin >> input; if (std::cin.fail() || numOfDigit(input) != 4 || contSameNum(input)) { std::cout << "Wrong input!" << std::endl; std::cout << "Try again!" << std::endl; CLEAR } else { std::cout << "Here is step by step computation for your input:"<