IB Computer Science Option D - OOP (SL)

Definition

Term

D.1 - Objects as a Programming Concept

Abstract entity that has data (properties and attributes) and can perform actions/methods.

"General blueprint"/Template for creating above. Example: Door

Specific objects of above. Example: Screen door

Represents classes as three compartments: Name, data/variables, actions/methods. Also depicts connections between multiple classes.

Breaking down problem into related objects in order to reduce complexity

One object depends on other objects, cannot function otherwise; this increases maintenance overheads. Represented with dashed arrow. Example: Vehicle uses an Engine

One object belongs to another object and none other. Example: Department has a Teacher, who cannot belong to another department unless this Department no longer exists.

Child/Subclass is a specialized form of parent/superclass, i.e. child/subclass has all data and actions/methods of parent/superclass; code will not have to be rewritten. Example: Student is a Person

Whole numbers. Represented by int or long, for example.

Numbers with decimal or fractional values.

Only holds two conditions: true or false.

Series of characters. Not really a primitive data type but a reference class

Name of information passed to method

Value passed onto method via above

D.2 - Features of OOP

Inclusion of both data and actions/methods into single component; access to such data and actions from outside of class is thereby restricted.

When multiple methods have same name but with different parameters (static), or when subclass overrides method of its superclass such that new method has different functions (dynamic).

Collections of pre-written classes that can be used by programmer while developing program.

Contrary to solo developer, can handle larger projects with more ideas but effective communication is required.

Dividing complex and large program into smaller sub-programs that can be implemented and tested on their own. These sub-programs may be reused in other programs.

D.3 - Program Development

Identifies an entity (as name suggests). Examples: name, gender, age

Keyword that serves as basic building block. Examples: char, int, double, boolean

Values of data from class unique to each object. Example: age

Data items passed to and from actions/methods. Can only be accessed inside the method that declares it.

Declared inside blocks/scope of code such as in methods/actions or loops.

When called, reads specific data value of object.

When called, modifies data value of object.

Special methods that allow creation of instantiations of objects to be created

Includes method name, parameters, and types. Example: setPrice(int price)

Value that is passed back when method is called

Can only be accessed by class defining it

Above condition + subclasses

Any class can access it

"Inherits from"

Belongs to class instead of specific instance; all objects share same value.

Holds any value from -2^31 to (2^31)-1, inclusive

Holds any value from -2^63 to (2^63)-1, inclusive

Can represent decimals

Represents Unicode character

Runs by: 1 - Declaring and initializing control variable, 2 - Checking if boolean expression is true (runs if true, terminates otherwise), 3 - After code is run, control variable is updated, 4 - Repeat 2. Common example: (int i = 0; i < n; i++)

Runs if boolean expression evaluates to true.

Holds fixed number of elements of same type (length is established during array initialization). Example: int[] ages = new int[10];

Examples include support for non-English text, date and time formatting, complex symbols, and localized content.