Introduction to C++ Classes and Objects

In C++, a class is a blueprint for creating objects, and an object is an instance of a class. Classes and objects are fundamental concepts in object-oriented programming (OOP). They allow you to model real-world entities and their behavior in your C++ programs. In this guide, we'll explore the basics of C++ classes and objects.

Defining a Class

A class is defined using the class keyword, followed by the class name and a code block that contains data members and member functions. Here's a basic class definition:

class ClassName {
public:
    // Data members (attributes)
    data_type member1;
    data_type member2;    // Member functions (methods)
    return_type method1(parameters);
    return_type method2(parameters);
    // ...
};
    

Example:

#include <iostream>
using namespace std;
class Person {
public:
    string name;
    int age;    void displayInfo() {
        cout << "Name: " << name << ", Age: " << age << endl;
    }
};
int main() {
    Person person1;
    person1.name = "John";
    person1.age = 30;    person1.displayInfo();    return 0;
}
    

In this example, we define a Person class with data members name and age, and a member function displayInfo that displays the person's information. We then create an object of the Person class and set its attributes before calling the displayInfo method.

Creating Objects

Objects are instances of classes. You create objects by specifying the class name followed by the object name and optional initial values. Objects can access the data members and member functions of their class.

Example:

int main() {
    Person person1;
    person1.name = "Alice";
    person1.age = 25;    Person person2;
    person2.name = "Bob";
    person2.age = 35;    person1.displayInfo();
    person2.displayInfo();    return 0;
}
    

In this code, we create two Person objects, person1 and person2, and set their attributes individually before calling the displayInfo method for each object.

Conclusion

C++ classes and objects are the foundation of object-oriented programming, enabling you to encapsulate data and behavior into reusable entities. As you continue your C++ journey, you'll explore more advanced topics, such as constructors, destructors, and object-oriented design principles.