How to implement Inheritance in C++? Inheritance with example?

 Inheritance is one of the key features of object-oriented programming, which allows you to create a new class that is a modified version of an existing class. In C++, you can implement inheritance using the class or struct keywords, along with the public, private, and protected access specifiers.

Here's an example of how to implement inheritance in C++:

c++
#include <iostream>

using namespace std;

// Define a base class
class Shape {
public:
    void setWidth(int w) {
        width = w;
    }

    void setHeight(int h) {
        height = h;
    }

protected:
    int width;
    int height;
};

// Define a derived class that inherits from Shape
class Rectangle: public Shape {
public:
    int getArea() {
        return (width * height);
    }
};

int main() {
    Rectangle rect;

    // Set the width and height of the rectangle
    rect.setWidth(5);
    rect.setHeight(10);

    // Print the area of the rectangle
    cout << "Area of the rectangle = " << rect.getArea() << endl;

    return 0;
}

In this example, we define a base class Shape with two protected data members width and height, and two public member functions setWidth() and setHeight() to set the values of these data members. We then define a derived class Rectangle that inherits from Shape using the public access specifier. The Rectangle class has one public member function getArea() that returns the area of the rectangle.

In the main() function, we create an object rect of the Rectangle class and set its width and height using the setWidth() and setHeight() member functions inherited from the Shape class. We then print out the area of the rectangle using the getArea() member function of the Rectangle class.

Note that by inheriting from the Shape class, the Rectangle class automatically gets access to the width and height data members, as well as the setWidth() and setHeight() member functions, without having to re-implement them. This allows us to reuse code and avoid duplicating code across different classes.