Object-Oriented Design relationship

• Recursion is an approach to problem-solving that relies on solutions to smaller instances of the same problem.
• In programming, recursion occurs when a procedure calls itself until a terminating condition is met.
• Recursion is achieved without explicit repetition constructs like "while" or "for" loops.
• Recursion breaks down problems into smaller subtasks.
• Algorithms presented recursively can often be presented iteratively, and vice versa.

Features of Stack ADT

• Stacks consist of a "chain" of data.
• Elements are "pushed" onto the top of the stack.
• Elements are "popped" from the top of the stack.
• Stacks follow the LIFO (Last-In, First-Out) approach.
• Accessing an element from an empty stack results in an error and should be avoided.

Features of Queue ADT

• Queues are composed of a "chain" of data.
• Elements are "enqueued" at the back of the queue.
• Elements are "dequeued" from the front of the queue.
• Queues follow the FIFO (First-In, First-Out) approach.
• An error occurs when attempting to access an element from an empty queue; avoid this.

Features of Binary Tree ADT

• Trees consist of nodes with two pointers: one to the left for smaller elements and one to the right for larger elements.
• Trees are structured from the root node.
• In a balanced tree, the root node contains the middle value of the dataset.
• They are naturally sorted.
• Searching is performed in a binary manner.

Coding Conventions

• Standards and conventions are established to make life easier
• They allow people to function and collaborate at an international level without difficulty
• A number of situations that do not follow a single international convention leads to difficulties in understanding and communication between people using different conventions for the same thing
• International conventions are important and allow for a common "language" that enables easier communication and collaboration between individuals across the globe.
• Programming has its own conventions to allow people from around the world to easily exchange code and be able to work around the same projects
• Following coding conventions can reduce cost, especially during maintenance.
• Code conventions are necessary to improve readability and allow engineers to quickly and fully understand previously written code.
• Code that follows internationally established conventions is easier to understand, alter, and maintain.
• Language Conventions: Most programming languages use English to remove a language barrier.
• Comment Conventions: Comments can be "block" (a.k.a. prologue) or "line" (a.k.a. inline).
• Block comments in Java are delimited by /* and */, spanning multiple lines.
• Line comments in Java are delimited by //.
• Comments are used to summarize code.

Object-Oriented Programming

• Object: An abstract entity describing data and actions, corresponding to real-world entities and a core aspect of OOP.
• Class: Abstract object entities from which specific objects can be built.
• Calling Methods: Sending messages to an object in order to perform actions in OOP.
• Objects cannot perform actions without specific data.
• The object has data that are specific to the object and accompany it throughout the execution of a program
• Classes, don't occupy memory space.
• Classes are Blueprints.
• A specific object that is instantiated from the class occupies enough memory to accommodate the object's data and actions.
• Unifies Modeling Language (UML): Visualizes software system design and models object-oriented programs.
• UML class diagrams depict classes within an object-oriented program and their collaborations.
• Illustrates classes as three-tier compartments, rectangles divided into 3 compartments
• The top compartment signifies the name of the class.
• The middle compartment contains a list of all the data that an object of this class will hold.
• The last compartment contains a list of all the actions that an object of this class will be able to perform.
• Actions are presented in the returnType: actionName(inputType) form.
• inputType is the type of data required by the specific action.
• returnType is the type of data returned after the action completes.
• If returnType is missing, the action does not return any data

UML Class Diagram Depictions

• UML class diagrams depict classes and display how they collaborate.
• Classes are connected, and UML diagrams represent these connections, describing the static structure of the system.
• Association: A line connecting two classes.
• Information can be attached to associations to increase clarity of complex programs
• Each association has two roles, each with a direction.
• The role may be named for clarity.
• Multiplicities indicate the number of objects of one class linked to one object of the other class and are placed at each end of the line.
• Inheritance: Takes advantage of similarities and is is an "is-a" or "is-like" relationship.
• Inheritance is displayed with hollow arrows in UML class diagrams.
• UML Class Diagrams may be created using just the names of classes to focus on associations, roles, multiplicities, and inheritances.
• UML class diagrams are used to depict how various objects are associated and how classes inherit data and actions (generalizations).
• Four relationships in UML diagrams: association, dependency, aggregation, and inheritance.

Relationships

• Association: The Simplest relationship between 2 or more objects, and it may have role labels.
• Dependency: S"Uses" relationship, the object is dependent on one or more objects in order to function
• Represented with the dashed arrow → the arrow leaves the object that depends on the object
• Aggregation: One object belongs to another object and no other (parent and child object)
• A hollow diamond followed by a line represents the aggregation relationship
• Inheritance: One object (child/subclass) is a specialized form of another object (parent/superclass).
• A hollow triangle followed by a line represents the inheritance relationships

Dependencies

• Dependencies are directional; object B can depend on A and vice-versa.
• Solutions using O-O programming deal with interdependent objects.
• Dependencies decrease code reuse and increase maintenance overhead.

Data and Action Organization

• Programs classify data into types determining meaning, storage, and manipulation.
• Common Data Types: integer numbers, real numbers, Booleans, and strings

Integer Numbers

• Integer Numbers represent a finite subset of mathematical integers.
• Integer Numbers can include negative values.
• Implementation depends on the hardware and language using a specific number of bits.

Real Numbers

• Real Numbers contains fractional values
• Real Numbers are approximations with range and precision trade-offs.
• Primitive Data: float and double (double has more precision & larger numbers)
• Booleans represent only true/false.
• Strings represent character series for display

Object Actions

• Object Actions can have multiple parameters and return one value at most.
• Actions use passed arguments as parameters and changes to parameters will not affect the arguments' values.
• Parameter: name of the information used in a method, function, or procedure.
• Argument: the value passed into a method, function, or procedure.

Object Oriented Programming Features

• Encapsulation – inclusion of both data and actions into a single component
• Inheritance – refers to that one object (child/subclass) is a specialized form of another object (parent/superclass) (1.3,1.4,1.6)
• A derived class inherits data and actions from an existing class.
• Polymorphism - means “many“ – the ability to have many forms
• The method that needs to be invoked for a particular method call depending on the number and types of parameters passed
• Allows for subclasses to alter any parent class actions and make them specific to their needs

Static Polymorphism

• During Static Polymorphism compiler is able to understand the method signatures and decide

Access

• Private – can be accessed only by the class that defines it
• Protected – Only the class that defines it and its subclasses can access it
• Public - any class can access it

Encapsulation

Plays the role of a protective wall that prevents data and actions from being accessed from outside a class, resulting in unwanted behavior

Encapsulation Advantages

• Data in a class can be made read or write only
• A class restricts the ways that its data and actions can be altered or called
• Outside the object, only the behavior of the object is apparent, hiding and protecting its internal workings

Inheritance Advantages

• Extensibility, Reusability, Information hiding, Overriding of actions
• Child classes may override parent actions in order to implement meaningful actions for their needs.
• Polymorphism provides a high degree of decoupling, action implementations are hidden, external programs use make sound or walk without knowing implementing object.

Object Libraries

• Object Libraries: Collection of pre-written classes that simplify projects with standard, tested code
• It allows for various functions and code reuse.

OOP Disadvantages

OOP Disadvantages: For small projects, with few developers and modules, OOP may increase complexity, development time, and maintenance cost.

• For small projects, can make programmers make the project too abstract.

Different Developer Roles

• Solo Developer: One person manages the entire development cycle, suitable for small-scale & quick changes, easier to decision.
• Team Developers: Groups are formed for larger projects, can bring various ideas to the table, and the weaknesses of some team members may end up undermining the group as a whole.

Modularity

• Modularity is effective if the program can be broken up into smaller, logical programs to test on their own.

Modularity Advantages

• Using this structure makes it easy to reuse sub-programs for other applications, less code needs to be written and easy to debug, black boxes.

Key elements

• Class – in OOP, defines a template through which objects may be created Provide specific data and actions
• Identifier - a name that identifies an entity, generated by alpha numeric sequences
• Note* It shouldn't begin with a ditgit
• Primitive - Common primitive types include: Characters (char): Primitive type that represents a character Integers (int, short, long, byte) Floating-point numbers (float, double) Boolean (bool): Primitive type that may take only one of two values, true or false
• Method – actions that are associated with an object and modified its data properties like Accessor and Mutator
• Signature - identifies the method – every method has it and Return value – value that is passed back, returned

This quiz assesses knowledge of relationships in object-oriented design, including aggregation, inheritance, and dependency. It also covers data types, real number representation, and recursion, along with the principles of problem-solving.