3.2 Inheritance (started)

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