C++ program to check whether the number is prime or not using class

Given an integer number, we have to check whether it is prime or not using the class and object approach.
Submitted by Shubh Pachori, on September 12, 2022

Example:

Input:
Enter Number : 19

Output:
19 is Prime.

C++ code to check whether the number is prime or not using the class and object approach

#include <iostream>
using namespace std;

// create a class
class IsPrime {
  // private data members
 private:
  int number;

  // a public function with a
  // int type parameter
 public:
  // getNumber() function to insert
  // the number
  void getNumber() {
    cout << "Enter Number : ";
    cin >> number;
  }

  // isprime() function to check if the
  // number is prime or not
  void isprime() {
    // initilaize two int type variable
    int index, check = 0;

    // for loop to check whether the number
    // is prime or not
    for (index = 2; index < number; index++) {
      // if condition to check if the number is
      // divisible by the index
      if (number % index == 0) {
        // print not prime if condition satisfied
        cout << number << " is not Prime." << endl;

        // increases check counter
        check++;

        // break to end the loop
        break;
      }
    }

    // if condition to check counter if
    // count = 0 then it will print prime
    if (check == 0) {
      cout << number << " is Prime." << endl;
    }
  }
};

int main() {
  // create an object
  IsPrime P;

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

  // calling isprime() function to check if
  // the number is prime or not
  P.isprime();

  return 0;
}

Output:

RUN 1:
Enter Number : 23
23 is Prime.

RUN 2:
Enter Number : 119
119 is not Prime.

Explanation:

In the above code, we have created a class IsPrime, one int type data member number to store the number, and public member functions getNumber() and isprime() to store the number and to check if the number entered is prime or not.

In the main() function, we are creating an object P of class IsPrime, inputting the number by the user using the getNumber() function, and finally calling the isprime() member function to check if the number entered is prime or not. The isprime() function contains the logic to check if the number entered is prime or not.