C++ Program to Define a Class and Create Objects

Implement a C++ Program to Define a Class and Create Objects

One of the key features that makes C++ a powerful language is its support for Object-Oriented Programming (OOP). OOP allows programmers to model real-world entities using classes and objects, making code modular, reusable, and easier to maintain.

🔹 What is a Class?

A class in C++ is a user-defined blueprint or prototype from which objects are created. It contains data members (variables) and member functions (methods) that operate on the data.

Syntax:

class ClassName {

  // Data members

  // Member functions

};

🔹 What is an Object?

An object is an instance of a class. When a class is defined, no memory is allocated until an object of that class is created.

✅ C++ Program: Define a Class and Create Objects

Let’s create a simple program that defines a class named `Student` and uses it to create and display student details.

#include <iostream>

using namespace std;

// Define the class

class Student {

private:

    int rollNo;

    string name;

public:

    // Method to input student data

    void inputDetails() {

        cout << "Enter Roll Number: ";

        cin >> rollNo;

        cout << "Enter Name: ";

        cin.ignore(); // To clear newline character from buffer

        getline(cin, name);

    }

    // Method to display student data

    void displayDetails() {

        cout << "\nStudent Details:\n";

        cout << "Roll Number: " << rollNo << endl;

        cout << "Name: " << name << endl;

    }

};

// Main function

int main() {

    // Create object of Student class

    Student s1;

    // Call class methods using object

    s1.inputDetails();

    s1.displayDetails();

    return 0;

}

🔍 Output Example

Enter Roll Number: 101

Enter Name: Vivek Bhardwaj

Student Details:

Roll Number: 101

Name: Vivek Bhardwaj

🧠 Explanation

Class Definition:

The `Student` class has two private data members: `rollNo` and `name`, and two public member functions: `inputDetails()` and `displayDetails()`.

Object Creation:

Inside the `main()` function, we create an object `s1` of type `Student`.

Method Invocation:

Using `s1`, we call `inputDetails()` to input the values and `displayDetails()` to print them.

`cin.ignore()` Usage:

  We use `cin.ignore()` to handle newline issues when mixing `cin` and `getline()`.