How Derived Class object is added to Base Class objects List
c#, inheritance, oop, polymorphism, upcasting
Solution
A `Circle` is a `Shape`, because `Circle` extends `Shape`. Because of that, you can always treat a `Circle` object as if it were a `Shape` since we can be absolutely sure that all of the operations that can be performed on a `Shape` can also be performed on a `Circle`.
Problem
Given the following code, I have inherited a class Circle from Shape: ``` class Shape { void Draw(); } class Circle : Shape { } void Main(string[] args) { Shape s = new Shape(); Shape s2 = new Shape(); Circle c = new Circle(); List<Shape> ShapeList = new List<Shape>(); ShapeList.Add(s); ShapeList.Add(s2); ShapeList.Add(c); } ``` How can `c` be added into the `ShapeList`?