Question

What are the design concepts and assumptions behind a class, an object and the relationship between them? What are the roles methods and static fields play in OOP?

Answer 1

In Object-Oriented Programming (OOP), a class is a blueprint for creating objects, while an object is an instance of a class. The relationship between a class and an object is that a class defines the structure of an object. Methods in OOP are used to perform actions or computations, while static fields are shared among all objects of a class.

Step-by-step explanation:

Design Concepts and Assumptions in OOP:

In Object-Oriented Programming (OOP), a class is a blueprint for creating objects, while an object is an instance of a class. The design concept behind a class is to define the common characteristics and behaviors that objects of that class will have. Assumptions made when designing a class include creating a hierarchy of classes to represent different levels of abstraction and encapsulating data and behaviors within the class.

Relationship between Class and Object:

In OOP, the relationship between a class and an object is that a class defines the structure (attributes and behaviors) of an object, while an object is an instance of a class that can be created and manipulated using the defined structure.

Roles of Methods and Static Fields in OOP:

In OOP, methods are functions or behaviors associated with an object or class, which are used to perform certain actions or computations. They define how objects or classes interact with each other and with the outside world. Static fields, on the other hand, are variables or data that are shared among all objects of a class. They hold values that are common to all instances of the class and can be accessed without creating an object.

Answer 2

Object-oriented programming (OOP) is a procedural language and based on classes associated with an object. Without classes and object relationship OOP is not possible. According to program's design concept classes provide abstraction and encapsulation with the help of object. Object have states and behaviors like cat has states like name, color and cat has also behaviors like wagging the tail, eating, jumping etc. A class forms template or blueprints for these states and behaviors because different cats have different behaviors and states.

Methods provide a way for encapsulation and accessing private class members with public methods and static fields are sometimes best alternative for global variable. We can use static field when it same for all and shared by all objects of that class and it can save memory because we do not have to initialize it for each object