---
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author: Louis Gallet
Date: 30/11/2023
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# Object Oriented Programming

<img src="https://i.imgur.com/qPsUYyd.jpg" alt="meme" style="zoom:50%;" />

## Introduction

- A programming paradigm
- Allows:
  - Model objects
  - Make objects interact with each other
- Objcts refer to complex variables

## Benefits and motivation

- Modularity
- Abstraction
- Productivity and reusability
- Security and encapsulation

## Concrete example

- When we develop a game with cars inside
- We develop the car one time and all other games can re-use the base of the car that we created
- We have access to characteristics
  - Model
  - Color
  - Fuel type
  - ...
- We also have the behavior of the car
  - Start
  - Accelerate
  - Stop

## Object

- Data part: object characteristcs
  - Attributes
  - Properties
  - Fields
  - ...
- Code part = oject behavior
  - Methods
  - Procedure

## Class

- Object = classs instance
- Class
  - New data type
  - Collection of objects
- Figuratively
  - Class = mold
  - Object = cake
- Class at compilation VS object at runtime

```csharp
public class MyFirstClass {
  public MyFirstClass() {} //constructor
}
MyFirstClass c = new MyFirstClass(); //new object
```

## Modelization

- First mandatory step

- Data modeling

- UML: Unified Modeling Language

  - Class diagram
  - Class Diagram example:![UML example](https://i.imgur.com/8zGdBkP.png)

  - Code example:

    ```csharp
    public class MuFirstCar {
      private string _color;
      public string GetColor(){
        return _color;
      }
      public void SetColor(string color){
        _color = color;
      }
    }
    ```

## OOP - Main principles

- Encapsulation
- Abstraction
- Inheritance (Héritage in french)
- Polymorphism