AP CSA Unit 2: Using Objects

Abs(int a)

used to find and return absolute values of an int

Assignment Operator

to assign a value to a variable (“=”)

Class

user-defined data types in object oriented programming

serves as a blueprints for creating objects by defining their attributes/instance variables

Constructor

a special method/procedure within a class that is used to create an instance of a class, always has same name of the class

to create an object/instance of a class by initializing the instance variables

ex. Object obj = new Object();

Encapsulation

the bundling of data and methods within a class, where the data is hidden from external access

ensures that an objects internal state remains consistent by controlling how it can be accessed or modified

IllegalArgumentException

an exception that occurs when a method receives an argument that is inappropriate or invalid for its intended purpose

indicates that there was an error in how arguments were passed into a method

IndexOf(String str)

used to find the index position of the first occurrence of a specified substring within a larger string

Inheritance

a concept in object-oriented programming where a class inherits the properties and behaviors of another class

allows for code reuse and promotes the creation of hierarchical relationships between classes

Return type (void)

return type in programming refers to the data type of the value that a method or function returns

in the case of “void,” it means that the method does not return any value

Length()

used to find the number of characters in a string

Math class

provides various mathematical operations and functions that can be performed on numeric data types

(includes methods for basic arithmetic operations, trigonometry, logarithms, random numbers generation, etc)

Methods

set of instructions for all object of a class

can manipulate data, interact with other objects, or return values

ex: simplify();

Null

a special value in programming that represents the absence of a value

means the object is referring to nothing

Object-oriented programming (OOP)

a programming paradigm that organizes code into objects, which are instances of classes

emphasizes the use of objects to represent real-world entities and their interactions

Objects

instance of a class that represent real-world entities or concepts

describes behavior/methods into a single entity

Overloading constructors

refers to the ability to have multiple constructors in a class, each with a different set of parameters (allows objects to be created with different initial states or configurations)

Parameters

variables declared in a method or function that receive values when the method is called, allow data to be passed into a method and enabled it to perform actions or calculations based on those values

Polymorphism

the ability of objects to take on multiple forms or have multiple types

allows different objects to be treated as instances of a common superclass, enabling flexibility and extensibility

Pow(double a, double b)

used to raise a number (a) to the power of another number (b)

Primitive data types

basic data types that are built into a programming language and represent simple values (include: double, int, boolean)

Random()

generates and returns a pseudorandom decimal value between 0.0-0.99

Reference types

data types in programming that store references or memory addresses rather than the actual value themselves (include objects, arrays, and strings)

Sqrt(double a)

calculates and returns the square root of a given number (a)

Substring(int beginIndex, int endIndex)

used to extract a portion of a string based on the specified beginning and ending indexes

returns a new string that contains the characters from the original string within the given range

Substring(in beginIndex)

used to extract part of an existing string starting from the specified beginning index up to the end of the original string

method call

calls/invokes the method code

String

object that holds sequences of characters (“a”, “b”, “$”)

String literal

set of characters enclosed in double quotes

ex: :”Kelly”

Reference variable

when an object points to a space in memory

Concatenation

operation of joining 2 strings together

ex: “Hello“ + “World” = “HelloWorld

\”

to add quotation marks in string

\\

to add backslash in string

\n

to add new line inside string