逐行注释以下代码：using System;using SystemCollectionsGeneric;public abstract class Shape public class Square Shape public double Side get; set; public class Circle Shape public double Radius get; se

// This code defines a hierarchy of shape classes and demonstrates how to use pattern matching with switch statements to determine the type of each shape.

// The Shape class is an abstract base class for all shapes. // The Square, Circle, and Triangle classes inherit from the Shape class and define their own properties.

// The Main method creates a list of Shape objects and adds instances of Circle, Square, and Triangle to the list. // It also adds a null Square object to demonstrate how pattern matching handles null values.

// The foreach loop iterates over each shape in the list and uses a switch statement to determine the type of each shape.

// The switch statement evaluates the type and/or value of the shape variable. // If the shape is a Circle, it prints the radius of the circle. // If the shape is a Square with a side greater than 10, it prints that it is a large square. // If the shape is a regular Square, it prints the side length. // If the shape is a Triangle, it prints the height. // If the shape is null, it prints that it could be a Square, Circle, or Triangle. // If the shape does not match any of the cases, it throws an ArgumentException.

// The output of the program will depend on the values of the properties of the shapes in the list.