​What is Object-Oriented Programming?

​OOP in Action

• The OOP paradigm is focussed on objects​ which represent parts of a computer program.

• ​You can create objects to represent physical things, like a human being.

• ​They can also be used for small parts of a larger program, like a widget in a user interface.

​Classes

• To create objects, you must first define a class.​

• ​A class is like a blueprint, it contains the plans for the data and behaviours an object should possess.

• ​You can create many objects from a single class.

• ​Just like you can make many houses from the same blueprint.

​Objects

• You can use a class to create enemies in a video game.

• ​One class details what information the enemies can hold and the behaviour it has.

• ​Objects would be the actual enemies in the game.

• ​Each ghost is an object in the game with a slightly different behaviour.

​Object Behaviour

• Ghost objects can choose their own behaviour based a the set of defined rules.

• ​Each ghost has its own attributes: colour, speed, name.

• ​They all move independently of each other.

​Classes and Objects

• ​One of the classes used in this program is called turtle.

• ​We import the class so that it can be used to make objects.

• ​The objects created are: blinky, pinky, inky and clyde.

• ​These are actually the variables used to store the objects.

​Introduction to C#

​C#

This programming language can be used to make interactive websites, mobile apps, video games, augmented reality (AR), virtual reality (VR), desktop applications, and back-end services – just to name a few.

For example, the mobile game Pokemon Go and the Stack Overflow website were built with frameworks that can be run with C# (Unity and ASP.NET, respectively).

• Unlike languages like Ruby and JavaScript, C# has you define the type of each data in a program.

• ​Assigning a type essentially tells a computer what operations can and cannot be performed on a piece of data.

• ​This style of coding helps programmers avoid a large class of errors that are common to Ruby and JavaScript.

​C# Data Types

​Hello World

​Console.WriteLine() is a command that prints text to a console.

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Whatever is in between the parentheses will be printed to the console!

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In this case it’s Hello World!

​Task: Start a new project in Visual Studio and change the code so that your own name is printed to the console!

​Getting Input

​We can also read input from a user. The command Console.ReadLine() captures text that a user types into the console.

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In this example, the program writes a question to the console and waits for user input. Once the user types something and presses Enter (or Return), the input is printed back out to the user.

​Comments

Text written in a program but not run by the computer is called a comment.

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In C#, anything after a // or between /* and */ is a comment.

Comments can:

​Provide context for why something is written the way it is:

​Help other people reading the code understand it faster:

​Ignore a line of code and see how a program will run without it: