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C# Full Course for free/14.OOP.md

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+# Classes
+
+In another file
+```C#
+class Messages()
+{
+    public static void Hello()
+    {
+        Console.WriteLine("Hello! Welcome to the program");
+    }
+    public static void Waiting()
+    {
+        Console.WriteLine("I am waiting for somtething");
+    }
+    public static void Bye()
+    {
+        Console.WriteLine("Bye! Thanks for visiting");
+    }
+}
+```
+
+```C#
+    Messages.Hello();
+```
+
+## Object
+
+Object is an instance of a class
+can have fields & nethods
+
+```C#
+class Human
+{
+    String name;
+    int age;
+
+    public void Eat()
+    {
+        Console.WriteLine(name + " is eating");
+    }
+    public void Sleep()
+    {
+        Console.WriteLine(name + " is sleeping");
+    }
+}
+```
+
+```C#
+// in the main class
+Human human1 = new Human()
+
+human1.name = "Rick";
+human1.age = 65;
+
+human1.Eat();
+human1.Sleep();
+
+Human human2 = new Human()
+
+human1.name = "Morty";
+human1.age = 16;
+
+human1.Eat();
+human1.Sleep();
+```
+
+## Construtor
+
+Constructor is a special method in a class
+
+```C#
+class Human
+{
+    String name;
+    int age;
+
+    public Human(String name, int age){
+        this.name = name;
+        this.age = age;
+    }
+
+    public void Eat()
+    {
+        Console.WriteLine(name + " is eating");
+    }
+    public void Sleep()
+    {
+        Console.WriteLine(name + " is sleeping");
+    }
+}
+
+```
+// in the main class
+
+Human human1 = new Human("Rick",65)
+Human human2 = new Human("Morty", 16)
+
+human1.Eat();
+human1.Sleep();
+human2.Eat();
+human2.Sleep();
+```
+
+## static
+
+static is a modifier to declare a static member, which belongs to the class itself
+rather than to any specific object
+
+```C#
+class Car
+{
+    String model;
+    public static int numberOfCars;
+
+    public Car(String model)
+    {
+        this.model = model;
+        numberOfCars++;
+    }
+    public static void StartRace()
+    {
+        Console.WriteLine("The race as begun !")
+    }
+}
+```
+
+```C#
+// in the main class
+
+Car car1 = new Car("Mustang");
+Car car2 = new Car("Corvette");
+ Console.WriteLine(Car.numberOfCars);
+
+Car.StartRace();
+```
+
+## overladed constructo
+
+Technique to create multiple constructors, with a different set of parameters but the same name.
+name + parameters = signature
+
+```C#
+class Pizza
+{
+    String bread;
+    String sauce;
+    String cheese;
+    String topping;
+
+    public Pizza(String bread,String sauce, String cheese, String topping)
+    {
+        this.bread = bread;
+        this.sauce = sauce;
+        this.cheese = cheese;
+        this.topping = topping;
+    }
+
+    public Pizza(String bread,String sauce, String cheese)
+    {
+        this.bread = bread;
+        this.sauce = sauce;
+        this.cheese = cheese;
+    }
+
+    public Pizza(String bread,String sauce)
+    {
+        this.bread = bread;
+        this.sauce = sauce;
+    }
+
+    public Pizza(String bread)
+    {
+        this.bread = bread;
+    }
+
+}
+```
+
+```C#
+// Main
+
+Pizza pizza = new Pizza("stuffed crust", "red sauce", "mozzarella");
+Pizza pizza1 = new Pizza("stuffed crust", "red sauce");
+```
+
+## inheritance
+
+1 or more child classes recieving fields, methods, etc. from a common parent
+
+```C#
+class Vehicle
+{
+    public int speed = 0
+    
+    public void go()
+    {
+        Console.WriteLine("this vehicle is moving !");
+    }
+}
+
+Class Car : Vehicle
+{
+    public int wheels = 4;
+}
+Class Bicycle : Vehicle
+{
+    public int wheels = 2;
+}
+Class Boat : Vehicle
+{
+    public int wheels = 0;
+}
+```
+
+```C#
+// Main
+
+Car car = new Car();
+Bicycle bicycle = new Bicycle();
+Boat boat = new Boat();
+
+Console.WriteLine(car.speed());
+Console.WriteLine(car.wheels());
+Console.WriteLine(car.go());
+
+Console.WriteLine(bicycle.speed());
+Console.WriteLine(bicycle.wheels());
+Console.WriteLine(bicycle.go());
+
+Console.WriteLine(boat.speed());
+Console.WriteLine(boat.wheels());
+Console.WriteLine(boat.go());
+```
+
+## abstract classes
+
+modifier that indicates missing components or incomplete implemetation
+
+```C#
+abstract class Vehicle
+{
+    public int speed = 0
+    
+    public void go()
+    {
+        Console.WriteLine("this vehicle is moving !");
+    }
+}
+
+Class Car : Vehicle
+{
+    public int wheels = 4;
+    int maxSpeed = 500; 
+}
+Class Bicycle : Vehicle
+{
+    public int wheels = 2;
+    int maxSpeed = 50; 
+}
+Class Boat : Vehicle
+{
+    public int wheels = 0;
+    int maxSpeed = 100; 
+}
+```
+
+```C#
+// Main
+Car car = new Car();
+Bicycle bicycle = new Bicycle();
+Boat boat = new Boat();
+Vehicle vehicle new Vehicle();
+// error can't instanciate
+```
+
+## array of object
+
+```C#
+Class Car 
+{
+    public String model;
+    public Car(String model)
+    {
+        this.model = model;
+    }
+}
+```
+
+```C#
+Car[] garage = new Car[3]
+
+Car car1 = new Car("Mustang");
+Car car2 = new Car("Corvette");
+Car car3 = new Car("Lambo");
+
+garage[0] = car1
+garage[1] = car2
+garage[2] = car3
+
+// or with anonymous object
+
+Car[] garage = {new Car("Mustang"), new Car("Corvette"), new Car("Lambo")}
+
+forach(Car car in garage)
+{
+    Console.WriteLine(car.model());
+}
+```
+