Allocating an object of abstract class type can be a tricky task for many developers. In this guide, we will delve into this topic and provide a step-by-step solution that will help you overcome this hurdle.
What is an Abstract Class?
An abstract class is a type of class that cannot be instantiated directly. It is used as a base class for other classes to inherit from. An abstract class can have both abstract and non-abstract methods. However, it must have at least one abstract method.
Allocating an Object of Abstract Class Type
To allocate an object of abstract class type, you must first create a concrete class that inherits from the abstract class. The concrete class must implement all the abstract methods of the abstract class.
class AbstractClass {
public:
virtual void abstractMethod() = 0;
};
class ConcreteClass : public AbstractClass {
public:
void abstractMethod() override {
// implementation goes here
}
};
int main() {
AbstractClass* obj = new ConcreteClass();
obj->abstractMethod();
delete obj;
return 0;
}
In the above example, we have created an abstract class AbstractClass with an abstract method abstractMethod(). We have then created a concrete class ConcreteClass that inherits from AbstractClass and implements the abstractMethod().
In the main() function, we have allocated an object of the abstract class type using the concrete class ConcreteClass. We have then called the abstractMethod() on the object and finally deleted the object.
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FAQ
Q1. Can an abstract class have a constructor?
Yes, an abstract class can have a constructor. However, it cannot be instantiated directly.
Q2. Can a concrete class inherit from multiple abstract classes?
Yes, a concrete class can inherit from multiple abstract classes.
Q3. Can a concrete class inherit from both abstract and non-abstract classes?
Yes, a concrete class can inherit from both abstract and non-abstract classes.
Q4. What happens if a concrete class does not implement all abstract methods of the abstract class?
If a concrete class does not implement all abstract methods of the abstract class, it becomes an abstract class itself and cannot be instantiated directly.
Q5. Can a concrete class override a non-abstract method of the abstract class?
Yes, a concrete class can override a non-abstract method of the abstract class.