SkillStorm

stacks

Stacks are last-in, first-out data structures Ex: undoing an action

Hierarchical inheritance

a parent class is inherited by many subclasses Class A ---> Class B ---> Class C

What is an Object?

an instance of a class real world entity has properties performs tasks

ArrayList Example

ArrayList<integer> myList = new ArrayList<>() ArrayList<Cat> myList = new ArrayList<cat>(25)

What is OOP?

Bottom up Objects & Classes Access modifiers More secure Supports overloading Ex; Python & Java

HashMap

provides a way to create key-value pairs. The key is used to lookup the value at constant time.

Multi level inheritance

where one can inherit from a derived classes Class A & Class B ----> Class C

single inheritance

Inheritance type where only one superclass exists. Class A ---> Class B

Hub

Physical Layer) (Multiport Repeater)(Active, Passive, intelligent)

Example of inheritance

Product Pid Name Price iphone extends Product Brand Tech Mobile extends product Ram Os Sd

example of polymorphism

Program that is executing an add function, can be Add(), Add(int a,int b)

Abstraction

"shows" only essential attributes and "hides" unnecessary information Enables multiple inheritance

Router

(similar to a switch, routes data packets based on IP address)

Polymorphism (MOMO)

Same Method performed in different ways method overloading Method Overriding

Example of an object & class?

A Human is an object, & student would be a class. A human would have tasks & the student class would have specific tasks

What is a class?

A blueprint that defines an objects variables and methods.

Switch

(Multiport bridge with a buffer)

Repeater

(Physical layer) (Regenerate signal)

Bridge

(data link) (A repeater but filters content on Mac address)(transparent, source)

Inheritance

Acquiring the properties of one class to another class. Child class inherits the Parents class properties Reusing Code

Encapsulation (G&S)

Binding variables and methods under single entity. Getters and setters are used to protect your data when creating classes.

Example of Abstraction

Download Android apps as .apk so we run .exe but we don't get the code that runs this function. So no methods

Name the 4 Pillars of OOP

Encapsulation Inheritance Abstraction Polymorphism

Arrays

Fixed length & cannot be changed Primitive data types and objects Does not insert, just assigns.

Array Example

Int[] myArray = new int[10] Int[] myArray = new int{1,2,3,4,5,6,7,8,9,10} Dog[] dogs = new Dog[25]

What is the format for writing an object?

Public Class Main{ public static void main(String[] args) Main myObj = new Main(); or p1 = MyClass() print(p1)

Queues

Queues are first-in, first-out Favors ordered data

Example of encapsulation

Setting the variables as private & using the Getter/Setter methods to place/extract the data. Data hiding & Reusing code.

What do the method of Getters and Setters do?

The getter method returns the value of the attribute. The setter method sets a parameter and assigns it to the attribute

Class can not communicate with each other so Objects are used. T/F?

True

Array List

Variable length & will automatically change as data does. Objects and generic data types(not primitive). Adds to tailend of array.

method overloading

When two methods have the same name, but different parameters. Favors Compile Time

Method Overriding

child class overwritting a method inherited from a parent class. Favors Run Time

Gateways

connect two networks together)

LinkedList

similar to ArrayList (index position), except that the elements are doubly linked to one another. So this linkage gives new methods for adding and removing from the beginning or end, which makes it an easy choice for implementing a stack or queue.