Dart Session 7 - Summary This session covers fundamental Object-Oriented Programming (OOP) concepts in Dart, including method overriding, polymorphism, abstract classes, named constructors, the late keyword, and enumerations. Key Topics Covered: • Override: The @override annotation in Dart allows a child class to redefine a method inherited from its parent. This is useful when customizing the behavior of an existing method while maintaining the class hierarchy. • Polymorphism: Polymorphism enables the same method to be used across different object types, promoting code reuse and flexibility. This is commonly seen when a base class defines a method that subclasses can override with their own specific implementations. • Abstract Class: An abstract class serves as a blueprint for other classes and cannot be instantiated directly. It can define abstract methods (methods without implementation) that must be implemented by its subclasses. This is useful for enforcing a common structure across multiple classes. • Named Constructor: Dart allows defining multiple constructors using named constructors. These provide additional ways to create an instance of a class, often used for better readability or when initializing objects with different parameter sets. • Late Keyword: The late keyword is used to declare a variable that will be initialized later, avoiding unnecessary memory allocation at the time of declaration. It is useful when dealing with non-nullable variables that will be assigned a value before being accessed. • Enum: An enumeration (enum) is a special data type used to define a fixed set of constant values. This is useful when a variable should only take one value from a predefined set of options, making the code more readable and preventing invalid assignments. Additional Notes: • Differences between late, const, and final: ◦ late: Delays variable initialization until first use. ◦ const: Declares compile-time constants. ◦ final: Declares runtime constants that can only be assigned once. This session provides essential insights into structuring Dart programs efficiently using OOP principles.