College pilote Mégrine Computer Science Project Object in Computer science Realised by : Mayssa Koubâa 2019 - 2020 1 PLAN 1 What is an object ? 2 1 3 How do objects collaborate ? What criteria allow as to classify something as an object? 2 1 What is an object ? “Something you can do things to” (G. Booch) An object = an entity that has its state and behavior - The object maintains its state in one or more variables ● Variable = a data named by an identifier - The object implements its behavior by the methods ● Method = a function associated with an object Behavior (methods) variable variable variable State (variables) ● An object is an IT entity that includes variables and methods The variables form a core of the object and the methods form an envelope that surrounds the 3 kernel and hides it to other objects in the program 1 What is an object ? Examples of real world objects - Dog with the state defined by its name, color, race, position, ... and behavior as: sitting, couch, brings, barks ... - Bike with the state defined by its number of speeds, current speed, color, ... and behavior as: accelerates, changes the speed ... accelerate Sits name color Position Lies brings Dog modeled as computer object slows Nb speeds current speed color Change speed Bike modeled as computer object 4 PLAN 1 What is an object ? 2 1 3 How do objects collaborate ? What criteria allow as to classify something as an object? 5 2 How do objects collaborate ? ● The object appears as a component of a program that contains many others ● It is through the interaction of its objects that the program acquires a higher level of functionality and complexity ● The objects interact with each other sending messages Changes the speed (first Speed) The message includes: - The target object to whom the message is addressed (the bike) - The name of the method to be performed (changeValue) You - The parameter ( or parameters) that the method needs (firstSpeed) The bike 6 PLAN 1 What is an object ? 2 1 3 How do objects collaborate ? What criteria allow as to classify something as an object? 7 1 3 What criteria allow as to classify something as an object In computer science, an object can be - a variable, - a data structure, - a function, - or a method, and as such, is a value in memory referenced by an identifier. In the class-based object-oriented programming paradigm, object refers to a particular instance of a class, where the object can be a combination of variables, functions, and data structures. 8 Thank you for attention 9