Simple Constructor Example Program For Find Prime Number In C++

Definition

In C++, Constructor is automatically called when an object( the instance of the class) create.It is a special member function of the class.
It has the same name of the class.
It must be a public member.
No Return Values.
Default constructors are called when constructors are not defined for the classes.

Simple Program  Find Prime Number Algorithm/Steps:

  • STEP 1:  Start the program.
  • STEP 2:  Declare the class as Prime with data members,
  •                   Member functions.
  • STEP 3:  Consider the argument constructor Prime() with integer
  •                   Argument.
  • STEP 4:  To call the function calculate() and do the following steps.
  • STEP 5:  For i=2 to a/2 do
  • STEP 6:  Check if a%i==0 then set k=0 and break.
  • STEP 7:  Else set k value as 1.
  • STEP 8:  Increment the value i as 1.
  • STEP 9:  Check whether the k value is 1 or 0.
  • STEP 10:If it is 1 then display the value is a prime number.
  • STEP 11:Else display the value is not prime.
  • STEP 12:Stop the program.

Syntax

class class-name {
    Access Specifier :
    Member - Variables
    Member - Functions
public:
    class-name() {
        // Constructor code 
    }

    //... other Variables & Functions
}

Example Program

/*  Example Program For Simple Constructor Example Program For Prime Number Overloading In C++
    little drops @ thiyagaraaj.com

    Coded By:THIYAGARAAJ MP             */

#include<iostream>
#include<conio.h>

using namespace std;

// Class Declaration

class prime {
    //Member Varibale Declaration
    int a, k, i;
public:

    prime(int x) {
        a = x;

        k = 1;
        {
            for (i = 2; i <= a / 2; i++)
                if (a % i == 0) {
                    k = 0;
                    break;
                } else {
                    k = 1;
                }
        }
    }

    void show() {
        if (k == 1)
            cout << "\n" << a << " is Prime Number.";
        else
            cout << "\n" << a << " is Not Prime Numbers.";
    }
};

//Main Function

int main() {
    int a;
    cout << "Enter the Number:";
    cin>>a;

    // Object Creation For Class
    prime obj(a);

    // Call Member Functions
    obj.show();
    getch();
    return 0;
}

Sample Output

Enter the Number:7
7 is Prime Number.