Polymorphism

OOP of Object-Oriented Design (Study Notes)

Definition: “In object-oriented programming, polymorphism is the concept of implementing objects that can take on multiple forms or behave differently depending on the context, all within a common interface.”

Purpose & Benefits:

• Flexibility and reuse through common interfaces.
• Method overriding.
• Reduced coupling.

Types of Polymorphism

Polymorphism in object-oriented programming is typically categorised into 2 main types:

Compile-Time(Static)

Method overloading allows a class to have multiple methods with the same name but different parameters. The compiler determines the appropriate method to call based on the number and type of arguments passed during compile time. Method overloading enhances code readability by using the same method name for similar operations with different parameters.

Run-Time(Dynamic)

Method overriding occurs when a subclass provides a specific implementation for a method already defined in its superclass. The method to be executed is determined at runtime based on the actual type of the object, not the reference type. This is often referred to as dynamic dispatch, a hallmark of runtime polymorphism.

Examples:

Minimal Example:

class Dog:
    def speak(self):
        print("Woof!!")

class Cat:
    def speak(self):
        print("Meow!!")

for pet in [Dog(), Cat()]:
    pet.speak()

Realistic Example:

class Manager:
    def do_work(self):
        print("Managing team")

class Developer:
    def do_work(self):
        print("Writing code")

staff = [Manager(), Developer()]
for member in staff:
    member.do_work()