Generalization and Specialization

Generalization and Specialization are two complementary processes that allow the creation of class hierarchies.

Generalization

Generalization involves creating a base or parent class (superclass) that defines common attributes and behaviors shared by multiple derived or child classes (subclasses). The base class captures the common features, and the derived classes add specialized features.

Specialization

Specialization on the other hand, focuses on the derived classes that inherit from a common base class. These subclasses provide specific details, attributes, or behaviors that differentiate them from the others while retaining the shared characteristics.

Let’s use an example to understand – modeling different types of animals. We will have a base class Animal representing shared properties and behaviors, and derived classes like Dog and Cat that specialize the general Animal class.

Below is the implementation of the above example:

C++

#include <iostream>
#include <string>
 
class Animal {
protected:
    std::string name;
 
public:
    Animal(const std::string& n)
        : name(n)
    {
    }
 
    void eat()
    {
        std::cout << name << " is eating." << std::endl;
    }
 
    virtual void makeSound()
    {
        std::cout << "An animal makes a generic sound."
                  << std::endl;
    }
};
 
class Dog : public Animal {
public:
    Dog(const std::string& n)
        : Animal(n)
    {
    }
 
    void makeSound() override
    {
        std::cout << name << " barks: Woof woof!"
                  << std::endl;
    }
 
    void fetch()
    {
        std::cout << name << " is fetching a ball."
                  << std::endl;
    }
};
 
class Cat : public Animal {
public:
    Cat(const std::string& n)
        : Animal(n)
    {
    }
 
    void makeSound() override
    {
        std::cout << name << " meows: Meow meow!"
                  << std::endl;
    }
 
    void scratch()
    {
        std::cout << name << " is scratching the furniture."
                  << std::endl;
    }
};
 
int main()
{
    Dog myDog("Rover");
    Cat myCat("Whiskers");
 
    myDog.makeSound();
    myCat.makeSound();
 
    myDog.fetch();
    myCat.scratch();
 
    return 0;
}

Output

Rover barks: Woof woof!
Whiskers meows: Meow meow!
Rover is fetching a ball.
Whiskers is scratching the furniture.

In this example:

The Animal class is the general or base class, encapsulating common attributes and behaviros shared by all animals.
The Dog and Cat classes are specialized or derived classes. They inherit from the Animal class, extending it with their specific attributes and behaviors.
The makeSound method is declared as virtual in the base class and overridden in the derived classes. This is a key feature of specialization, allowing each animal to make its specific sound.
The fetch method is specific to the Dog class, and the scratch method is specific to the Cat class. These methods demonstrate how specialization allows us to add unique behaviros to individual subclasses.

Object Model | Object Oriented Analysis & Design

Object-Oriented Programming (OOP) is a fundamental paradigm in modern software development that has transformed the way we design, build, and maintain software systems. OOP is centered around the concept of objects, which are self-contained, reusable units that encapsulate both data and the operations that can be performed on that data. This approach mirrors real-world modeling, making it easier to understand, manage, and expand software projects.

Important Topics for the Object Model

Objects and Classes
Encapsulation and Data Hiding
Message Passing
Inheritance
Polymorphism
Generalization and Specialization
Association and Aggregation
Benefits of Object Model
Conclusion

Generalization and Specialization

Generalization

Specialization

C++

Object Model | Object Oriented Analysis & Design

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