添加Lesson13

C#核心/Lesson13_继承-李氏替换原则/Program.cs

@@ -0,0 +1,10 @@
+namespace Lesson13_继承_李氏替换原则
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Console.WriteLine("Hello, World!");
+        }
+    }
+}