111

cs5/5_6/5_6.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <RootNamespace>_5_6</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

cs5/5_6/5_6.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.14.36616.10 d17.14
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "5_6", "5_6.csproj", "{93E19541-FEF3-4004-878B-615610904002}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{93E19541-FEF3-4004-878B-615610904002}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{93E19541-FEF3-4004-878B-615610904002}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{93E19541-FEF3-4004-878B-615610904002}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{93E19541-FEF3-4004-878B-615610904002}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {49161CD3-DF8F-4571-A2D5-DDDC82BFFCC2}
+	EndGlobalSection
+EndGlobal

cs5/5_6/Program.cs

@@ -0,0 +1,61 @@
+namespace _5_6
+{
+    public interface ICDPlayer
+    {
+        void Play();
+        void Stop();
+        void PreviousTrack();
+        void NextTrack();
+        int CurrentTrack
+        {
+            get;
+        }
+    }
+    public class CDPlayer : ICDPlayer
+    {
+        private int currentTrack = 0;
+        public void Play()
+        {
+            Console.WriteLine("启动CD。。。");
+        }
+        public void Stop()
+        {
+            Console.WriteLine("停止播放CD。。。");
+        }
+        public void PreviousTrack()
+        {
+            if (currentTrack > 0)
+            {
+                currentTrack--;
+            }
+            Console.WriteLine("上一音轨：");
+        }
+        public void NextTrack()
+        {
+            Console.WriteLine("下一音轨：");
+            currentTrack++;
+        }
+        public int CurrentTrack
+        {
+            get
+            {
+                return currentTrack;
+            }
+        }
+    }
+    public class Program
+    {
+        static void Main(string[] args)
+        {
+            CDPlayer mycd = new CDPlayer();
+            mycd.Play();
+            Console.WriteLine("当前音轨：" + mycd.CurrentTrack);
+            mycd.NextTrack();
+            Console.WriteLine("当前音轨：" + mycd.CurrentTrack);
+            mycd.PreviousTrack();
+            Console.WriteLine("当前音轨：" + mycd.CurrentTrack);
+            mycd.Stop();
+
+        }
+    }
+}