What is the relationship between LSP and polymorphism?

What is the relationship between LSP and polymorphism?

The Liskov Substitution Principle (LSP) is a key concept in object-oriented programming that relates to polymorphism. It states that objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program. This means that if a class is a subclass of another, it should be able to stand in for its parent class without causing errors.

Can you give me an example of LSP in action?

Sure! Imagine you have a class Bird with a method fly(). If you create a subclass Penguin that cannot fly, substituting Penguin for Bird would violate LSP. Instead, you could create an interface FlyingBird for birds that can fly, ensuring that only appropriate subclasses implement the fly() method.

How does this relate to code maintainability?

Adhering to LSP improves code maintainability by ensuring that subclasses can be used interchangeably with their parent classes. This reduces the risk of introducing bugs when modifying or extending code, as the behavior remains consistent across different implementations.

What are some common pitfalls to avoid with LSP?

Common pitfalls include creating subclasses that alter the expected behavior of the parent class, or failing to implement all required methods of an interface. This can lead to unexpected errors and violate the principle.