Understanding Liskov Substitution Principle with Real Construction Examples In software development, especially when building systems like construction expense tracking or invoice management apps, it is crucial to ensure your object-oriented design is maintainable and safe. One of the SOLID principles that guarantees reliability in inheritance is the  Liskov Substitution Principle (LSP) . The Liskov Substitution Principle states that objects of a subclass should be replaceable for objects of the base class without changing the correctness of the program. In practical terms, wherever you use a base class, you should be able to plug in any of its derived classes without unexpected behavior. Let’s explore how LSP applies in real-world construction scenarios like invoice processing, expense tracking, and payment handling.   Key Principle: Behavior Preservation                   ...

Liskov Substitution Principle (LSP) Liskov Substitution Principle (LSP) states that objects of a base class should be replaceable by objects of a derived class without altering the correctness of the program. In other words, derived classes must behave in such a way that they can stand in for their base classes without breaking the program.   Key Principles A subclass must not break the behavior expected from the base class. Derived classes should extend behavior, not override it with contradictory logic. No side effects or errors should occur when using a subclass in place of a base class. Method contracts (preconditions and postconditions) should be maintained or strengthened. LSP promotes safe polymorphism — you should be able to use a subclass object wherever a base class object is expected.   LSP Violation Example class Rectangle {     public virtual int Width { get; set; }   ...