How do I implement abstract classes in C++?

How do I implement abstract classes in C++?

To implement abstract classes in C++, you need to declare at least one pure virtual function using the syntax virtual void functionName() = 0;.

Can you give me an example of an abstract class?

Sure! Here's a simple example:

class Shape {
public:
    virtual void draw() = 0; // Pure virtual function
};

class Circle : public Shape {
public:
    void draw() override {
        // Implementation for drawing a circle
    }
};

What happens if I don't implement the pure virtual function?

If you don't implement the pure virtual function in a derived class, that derived class will also become abstract, and you won't be able to instantiate it.

Can I have multiple pure virtual functions in an abstract class?

Yes, you can have multiple pure virtual functions in an abstract class. This allows you to define a common interface for derived classes.