From 6635f23a7f3ba394c5abe219748e972a417031b2 Mon Sep 17 00:00:00 2001
From: Jason Zhu <jasonzhuyq@outlook.com>
Date: Mon, 9 Aug 2021 23:03:02 +1000
Subject: [PATCH] 3.2 Inheritance (started)

---
 chap03.md | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/chap03.md b/chap03.md
index 19c6205..d36657d 100644
--- a/chap03.md
+++ b/chap03.md
@@ -373,6 +373,38 @@ string name = nameof(count); // name is "count"
 
 ## 3.2 Inheritance
 
+**Subclass** inherit from **Superclass**
+
+e.g. define class inheritance
+```csharp
+// Superclass
+public class Asset
+{
+    public string Name;
+}
+
+// Subclass
+public class Stock : Asset
+{
+    public long SharesOwned;
+}
+public class House : Asset
+{
+    public decimal Mortgage;
+}
+```
+
+e.g. use classes
+```csharp
+Stock msft = new Stock { Name = "MSFT",
+                         SharesOwned = 1000 };
+Console.WriteLine(msft.Name); // MSFT
+Console.WriteLine(msft.SharesOwned); // 1000
+
+House mansion = new House { Name = "Mansion",
+                            Mortgage = 2500000 };
+```
+
 ### 3.2.1 Polymorphism
 
 ### 3.2.2 Casting and Reference Conversions