1. What is an Object Anyway?
IMAT1604 Visual Web Development

2. Stuff to memorise this Week
"A function is a named section of code that does one thing well"

3. What is an Object Anyway?
What is a word?
Think about the following word…
Shop
What springs to mind?
A Specific Shop?
The act of shopping?

4. Creating Instructions
A word on its own isn’t much use to us however when we combine it with other words we can create instructions.
“I want you to go to the shop and get me a tin of peas.”

5. Words are Really Just Symbols
What is this?

6. What if we add other symbols?
Traffic lights and words on a page are all the same they are all symbols that we look at and assign meaning.

7. What is Programming?
Programming is about using words and symbols to communicate with a Computer
As with our example above we use words / symbols to create instructions or functions that the computer will follow and perform some task.
Functions are organised into classes – text files

8. Harry Potter What makes Hermione Granger so irritating?
Why is Ron Weasley more relatable?
We need to use the right words correctly

9. Fight or Flight? Lots of errors Not sure about the tutor
Class at inconvenient time
Not getting it
The importance of determination

10. The Importance of Vocabulary
“Shop, street, road, post box, lamp post, post code, house, flat, house number, left, right ahead, distance, time, street sign, landmark.”
These words make up the vocabulary of the streets and roads. We are familiar with these words and can easily make up instructions (functions) using these words.
“You want to walk down that street for 10 meters then turn left at the post box. You will then see a sign to the railway station. Follow that sign for 5 meters and the shop is on the left.”

11. Computer Programming Introduces a new Vocabulary
“Class, object, assignment, sequence, variable, RAM, parameter, data type, function, method, property, selection, sequence, integer, string.”

12. The Computer Programmer
The person who knows how to write the correct words / symbols to tell the computer what to do
Computers copy and process data
Data is made of binary numbers
Nobody really likes binary
We need a set of commands to control data

13. First Look at Some C# Code
What is wrong with this?

14. The Problem Computers are really fussy
Spotting errors can be difficult at first
This gets easier with practice
Take a look at the following…
Int32 Name; - Variable
Name(); - Function
“Name” - A string of letters
.Name - A method or a property (Probably a property)
//Name - A comment
(Name) - A parameter

15. New Terms to Understand
Function
Method
Property
Class
Instantiation
Object

16. Functions
“A function is a named section of code that does one thing well.”

17. Functions are building blocks in programming
Functions are used to make
Methods
Properties
Unit tests
Event handlers
Constructors
(Like bread makes toast!)

18. Methods and Properties
Tells the object to perform an action
E.g. Multiply
Property
Allows us to get or change the settings of an object
E.g. Count
(This will be confusing at first!)

19. Classes
A class is a text file that contains related functions making them easier to manage
Classes are like recipe books
Recipe books dedicated to specific regions
Classes dedicated to specific sets of functionality
A student manager class might contain…
Methods
.AddStudent
.UpdateStudent
.DeleteStudent
Properties
.Count
.HighestStudentGrade

20. So what is an Object Anyway?
An object is the name we give to a class file so that we may access its methods and properties
The object in this code is MyStudents
Made up by the programmer
Associates the word with the class file clsStudents
Allowing us to access the function/method AddStudent

21. Instantiation Stuff in green called comments
Create an object MyCompter referencing the code in the class file clsComputer
Invokes the function/method TurnOff
Instantiation is the act of creating an object from a class.

22. Summary
Programming is about using words and symbols to communicate with a Computer
We need a system for writing lists of instruction for the computer that makes reasonable sense to human beings
We also have some key words for you to start getting to grips with…
Function A function is a named section of code that does one thing well
Property a property allows us to read or change the settings of an object
Method A method tells an object to perform an action
Class A class file is a text file that stores functions for a specific task
Object An object is the name we give to a class file so that we may access its methods and properties
Instantiation Instantiation is the act of creating an object from a class