添加Lesson12的练习

C#核心/C#核心.sln

@@ -13,6 +13,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson11_封装-内部类
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson13_继承-李氏替换原则", "Lesson13_继承-李氏替换原则\Lesson13_继承-李氏替换原则.csproj", "{06C184C2-C60B-4CFC-B3B8-7A8E0754D725}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson12_继承_继承的基本概念练习", "Lesson12_继承_继承的基本概念练习\Lesson12_继承_继承的基本概念练习.csproj", "{6FCF4496-0115-4C1F-A126-655CA118ADE9}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -39,6 +41,10 @@ Global
 		{06C184C2-C60B-4CFC-B3B8-7A8E0754D725}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{06C184C2-C60B-4CFC-B3B8-7A8E0754D725}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{06C184C2-C60B-4CFC-B3B8-7A8E0754D725}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6FCF4496-0115-4C1F-A126-655CA118ADE9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6FCF4496-0115-4C1F-A126-655CA118ADE9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6FCF4496-0115-4C1F-A126-655CA118ADE9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6FCF4496-0115-4C1F-A126-655CA118ADE9}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

C#核心/Lesson12_继承_继承的基本概念练习/Lesson12_继承_继承的基本概念练习.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

C#核心/Lesson12_继承_继承的基本概念练习/Program.cs

@@ -0,0 +1,34 @@
+namespace Lesson12_继承_继承的基本概念练习
+{
+    class Human
+    {
+        public string name;
+        public int age;
+        public void Speak()
+        {
+            Console.WriteLine("说话");
+        }
+    }
+    class Warrior : Human
+    {
+        public int atk;
+        public void Attack()
+        {
+            Console.WriteLine("攻击");
+        }
+    }
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Console.WriteLine("Hello, World!");
+            Warrior w = new Warrior();
+            w.name = "HK";
+            w.age = 18;
+            w.Speak();
+            w.atk = 5;
+            w.Attack();
+
+        }
+    }
+}