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

2 min read Updated June 30, 2026
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About this program

This is an example program in c c class example programs. Read the concept first: Introduction of Classes (OOP), then study the code and output below.

Definition

The C++ programming language allows programmers to separate program-specific data types through the use of classes. Classes define types of data structures and the functions that operate on those data structures. Instances of these data types are known as objects and can contain member variables, constants, member functions, and overloaded operators defined by the programmer.

Syntactically, classes are extensions of the C struct, which cannot contain functions or overloaded operators.

Prime Number:

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Syntax

class classname {
    Access - Specifier :
    Member Varibale Declaration;
    Member Function Declaration;
}

Example Program

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

    Coded By:THIYAGARAAJ MP             */

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

using namespace std;

// Class Declaration

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

    prime(int x) {
        a = x;
    }

    // Object Creation For Class

    void calculate() {
        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.calculate();
    obj.show();
    getch();
    return 0;
}

Sample Output

Enter the Number:10
10 is Not Prime Numbers.

Enter the Number:7
7 is Prime Number.

Learn the concept first, then study the code:

Frequently Asked Questions

What does this C++ program do?
It is a C++ example program that demonstrates Simple Class For Find Prime Number, including the complete source code and the expected sample output.
How do I compile and run this C++ program?
Save the code in a `.cpp` file, compile it with `g++ filename.cpp -o program`, then run it with `./program` (or `program.exe` on Windows).
What concepts does this example use?
This example uses loops to iterate over data, conditional logic and reading user input, illustrating a common pattern in C++ programming.

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