C++ program to check if the number is kaprekar or not using class

Given a number, we have to check whether it is kaprekar number or not using the class and object approach.
Submitted by Shubh Pachori, on October 05, 2022

Example:

Input:
Enter Number : 6174

Output:
It is not a Kaprekar Number!

C++ code to check if the number is kaprekar or not using the class and object approach

#include <iostream>
#include <math.h>

using namespace std;

// create a class
class Kaprekar {
  // private data member
 private:
  int number;

  // public member functions
 public:
  // getNumber() function to insert number
  void getNumber() {
    cout << "Enter Number : ";
    cin >> number;
  }

  // isKaprekar() function to check if the number
  // is kaprekar is or not
  void isKaprekar() {
    // initialising  int type variables to 
    // perform operations
    int check = 0, parts, square, squaredigits = 0, digits, sum;

    // if condition to check if number
    // is equal to 1
    if (number == 1) {
      check = 1;
    }

    // calculating square of the number
    square = number * number;

    // calculating digits of the square of number
    while (square) {
      squaredigits++;
      square /= 10;
    }

    // recalculating square of number
    square = number * number;

    // for loop to check the number
    for (digits = 1; digits < squaredigits; digits++) {
      // calculating power
      parts = pow(10, digits);

      // if condition to check if number is
      // equal to calculated power
      if (parts == number) {
        continue;
      }

      // sum of quotient and remainder
      // of square by parts
      sum = square / parts + square % parts;

      // if condition to check if sum is 
      // equal to the number
      if (sum == number) {
        check = 1;
      }
    }

    if (check) {
      cout << "It is a Kaprekar Number!" << endl;
    } else {
      cout << "It is not a Kaprekar Number!" << endl;
    }
  }
};

int main() {
  // create an object
  Kaprekar K;

  // calling getNumber() function to
  // insert the number
  K.getNumber();

  // calling isKaprekar() function to check the
  // number if it is a kaprekar number
  K.isKaprekar();

  return 0;
}

Output:

Enter Number : 4879
It is a Kaprekar Number!

Explanation:

In the above code, we have created a class Kaprekar, one int type data member number to store the number, and public member functions getNumber() and isKaprekar() to store and to check the given integer number is a kaprekar number or not.

In the main() function, we are creating an object K of class Kaprekar, reading an integer number by the user using the getNumber() function, and finally calling the isKaprekar() member function to check the given integer number. The isKaprekar() function contains the logic to given check the number and printing the result.