From 1137d1b922b4e95cf3b3f77361f913f08c172707 Mon Sep 17 00:00:00 2001
From: Jason Zhu <jasonzhuyq@outlook.com>
Date: Mon, 22 Feb 2021 22:58:49 +1100
Subject: [PATCH] Finished Chaining Constructors

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 csharp_fundamentals/8_oop.md | 57 ++++++++++++++++++++++++++++++++++++
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+# Module 8. Object-oriented Programming with C#
+
+## The Pillars of OOP
+
+3 pillars
+* **Encapsulation**: hide details.
+  * Methods; Properties; Access modifiers;
+* **Inheritence**: Reuse code
+* **Polymorphism**: Have object behave differently
+
+## Deriving from a Base Class
+
+Reference:
+* [Inheritance in C#](https://dotnettutorials.net/lesson/inheritance-c-sharp/)
+* [Inheritance in C# and .NET (C# guide)](https://docs.microsoft.com/en-us/dotnet/csharp/tutorials/inheritance)
+
+Syntax:
+
+```csharp
+public class ChildClass : ParentClass
+{
+    //...
+}
+```
+
+## Chaining Constructions
+
+Reference:
+* [Call Chain of Constructors in C#](https://app.pluralsight.com/guides/call-chain-constructors-csharp)
+
+When constructor of parent class has parameter, we can chain the constructor of child class using `base(param1, ...)`
+
+Syntax:
+
+```csharp
+    public class ParentClass
+    {
+
+        public ParentClass(string name)
+        {
+            Name = name;
+        }
+        public string Name
+        {
+            get;
+            set;
+        }
+    }
+
+    public class ChildClass : ParentClass
+    {
+        public ChildClass(string name) : base(name)
+        {
+            Name = name;
+        }
+    }
+```
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