Differences of Class to Object to Method and the Importances of the following buttons

CLASS

In object-oriented programming, a class is a construct that is used as a blueprint to create instances of itself – referred to as class instances, class objects, instance objects or simply objects. A class defines constituent members which enable these class instances to have state and behavior. Data field members (member variables or instance variables) enable a class object to maintain state. Other kinds of members, especially methods, enable a class object's behavior. Class instances are of the type of the associated class.

A class usually represents a noun, such as a person, place or (possibly quite abstract) thing, or something nominalized. For example, "Banana" is an instance of the class "Fruit" (a "Fruit" object). It is of the type "Fruit".

Classes consist of and are composed from structural and also behavioral constituents, though there may not be a requirement to include any structural or behavioral constituents at all. Programming languages that include classes as a programming construct offer support for various class-related features. These features, and the syntaxes with which they are provided, vary greatly. Various control features such as member access specifiers may be provided by a language.

Structure

A class contains data field descriptions (or properties, fields, data members, attributes), i.e., field types and names, that will be associated with either per-instance or per-class state variables at program run time. In most languages, the structure as defined by the class determines how the memory used by its instances will be laid out. Note: Other implementations are possible such as wherein objects are structured as associative key-value containers (Python).

Some programming languages support specification of invariants as part of the definition of the class, and enforce them through the type system. Encapsulation of state is necessary for being able to enforce the invariants of the class.

Every class implements (or realizes) an interface by providing structure (i.e. data and state) and method implementations (i.e. providing code that specifies how methods work). There is a distinction between the definition of an interface and the implementation of that interface. In most languages, this line is usually blurred, because a class declaration both defines and implements an interface. Some languages, however, provide features that help separate interface and implementation. For example, an abstract class can define an interface without providing implementation.

Languages that support class inheritance also allow classes to inherit interfaces from the classes that they are derived from. In languages that support access specifiers, the interface of a class is considered to be the set of public members of the class, including both methods and attributes (via implicit getter and setter methods); any private members or internal data structures are not intended to be depended on by client code and thus are not part of the interface.

The object-oriented programming methodology is designed in such a way that the operations of any interface of a class are usually chosen to be independent of each other. It results in a layered design where clients of an interface use the methods declared in the interface. An interface places no requirements for clients to invoke the operations of one interface in any particular order. This approach has the benefit that client code can assume that the operations of an interface are available for use whenever the client holds a valid reference to the object.

OBJECT

In computer science, an object is any entity that can be manipulated by the commands of a programming language, such as a value, variable, function, or data structure. (With the later introduction of object-oriented programming the same word, "object", refers to a particular instance of a class)

"Objects" are the foundation of object-oriented programming, and are fundamental data types in object-oriented programming languages. These languages provide extensive syntactic and semantic support for object handling, including a hierarchical type system, special notation for declaring and calling methods, and facilities for hiding selected fields from client programmers. However, objects and object-oriented programming can be implemented in any language.

Objects are used in software development to implement abstract data structures, by bringing together the data components with the procedures that manipulate them. Objects in object-oriented programming are key in the concept of inheritance; thereby improving program reliability^{[attribution needed]}, simplification of software maintenance^{[attribution needed]}, the management of libraries, and the division of work in programmer teams. Object-oriented programming languages are generally designed to exploit and enforce these potential advantages of the object model. Objects can also make it possible to handle very disparate objects by the same piece of code, as long as they all have the proper method.

Properties of an object

Three properties characterize objects:

1. Identity: the property of an object that distinguishes it from other objects
2. State: describes the data stored in the object
3. Behavior: describes the methods in the object's interface by which the object can be used 

METHOD

In object-oriented programming, a method is a subroutine (or procedure or function) associated with a class. Methods define the behavior to be exhibited by instances of the associated class at program run time. Methods have the special property that at runtime, they have access to data stored in an instance of the class (or class instance or class object or object) they are associated with and are thereby able to control the state of the instance. ^[1] The association between class and method is called binding. A method associated with a class is said to be bound to the class. Methods can be bound to a class at compile time (static binding) or to an object at runtime (dynamic binding).^[2]