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Classes

In C++, a class is a blueprint for creating objects. It defines the properties (data members) and behaviors (member functions) that objects of that class will have. Classes are fundamental to object-oriented programming (OOP) and provide a way to model and organize data and functionality. Here's how define and use classes in C++:

Defining a Class:

To define a class in C++, use the class keyword followed by the class name and a pair of curly braces { } to enclose the class members. Here's a simple example:

Program:

class MyClass {
public:
    // Data members (properties)
    int myData;

    // Member functions (methods)
    void setData(int data) {
        myData = data;
    }

    int getData() {
        return myData;
    }
};

In this example, it is defined a class named MyClass with a single data member myData and two member functions, setData and getData.

Creating Objects:

Once defined a class, it can create objects (instances) of that class by specifying the class name followed by the object name:

Program:

int main() {
    MyClass obj1; // Creating an object named obj1 of the MyClass class
    MyClass obj2; // Creating another object named obj2

    obj1.setData(42); // Using a member function to set data
    obj2.setData(10);

    int value1 = obj1.getData(); // Using a member function to get data
    int value2 = obj2.getData();

    return 0;
}
Accessing Class Members:

it can access the data members and member functions of a class using the dot . operator:

Program:

int main() {
    MyClass obj;
    obj.myData = 20; // Accessing and modifying a data member
    obj.setData(30); // Calling a member function

    int data = obj.getData(); // Accessing data through a member function

    return 0;
}
Constructor and Destructor:

A constructor is a special member function used to initialize the object when it is created. A destructor is a special member function used to clean up resources when an object is destroyed. C++ provides default constructors and destructors, but it can define own:

Program:

class MyClass {
public:
    int myData;

    // Constructor
    MyClass(int data) {
        myData = data;
    }

    // Destructor
    ~MyClass() {
        // Cleanup code, if needed
    }
};
Access Specifiers:

C++ provides access specifiers (public, private, and protected) to control the visibility and access of class members. By default, class members are private.0

public: Members declared as public are accessible from anywhere in the program.

private: Members declared as private are only accessible within the class.

protected: Members declared as protected are accessible within the class and its derived classes.

Program:

class MyPrivateClass {
private:
    int myPrivateData;

public:
    void myPublicFunction() {
        myPrivateData = 42; // It can access private data within the class
    }
};

These are the fundamental concepts of defining and using classes in C++. Classes provide a way to encapsulate data and behavior, enabling to create reusable and organized code.


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