添加Lesson5

2025-10-13 09:28:20 +08:00
parent 6cc1b0d4f9
commit 24da5481a1
5 changed files with 201 additions and 0 deletions
@@ -21,6 +21,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson4_Hashtable", "Lesson
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson4_Hashtable练习题", "Lesson4_Hashtable练习题\Lesson4_Hashtable练习题.csproj", "{962C9536-7CD7-4F5A-9D1E-1DCF986953D4}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson5_泛型", "Lesson5_泛型\Lesson5_泛型.csproj", "{8ECE6977-E08D-4089-9053-DFFD9864AB81}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson5_泛型练习", "Lesson5_泛型练习\Lesson5_泛型练习.csproj", "{524E1BC4-FE9A-4186-B7EE-A04323E98696}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -63,6 +67,14 @@ Global
 		{962C9536-7CD7-4F5A-9D1E-1DCF986953D4}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{962C9536-7CD7-4F5A-9D1E-1DCF986953D4}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{962C9536-7CD7-4F5A-9D1E-1DCF986953D4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8ECE6977-E08D-4089-9053-DFFD9864AB81}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8ECE6977-E08D-4089-9053-DFFD9864AB81}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8ECE6977-E08D-4089-9053-DFFD9864AB81}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8ECE6977-E08D-4089-9053-DFFD9864AB81}.Release|Any CPU.Build.0 = Release|Any CPU
+		{524E1BC4-FE9A-4186-B7EE-A04323E98696}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{524E1BC4-FE9A-4186-B7EE-A04323E98696}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{524E1BC4-FE9A-4186-B7EE-A04323E98696}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{524E1BC4-FE9A-4186-B7EE-A04323E98696}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -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>
@@ -0,0 +1,136 @@
+using System.Runtime.InteropServices;
+using static System.Net.Mime.MediaTypeNames;
+
+namespace Lesson5_泛型
+{
+    #region 知识点一 泛型是什么
+    //泛型实现了类型参数化，达到了代码重用的目的
+    //通过类型参数化来实现同一份代码上操作多种类型
+
+    //泛型相当于类型占位符
+    //定义类或方法时使用替代符代表变量类型
+    //当真正使用类或方法时再具体指定类型
+    #endregion
+
+    #region 知识点二 泛型分类
+    //泛型类和泛型接口
+    //基本语法：
+    //class 类名<泛型占位符>
+    //interface 接口名<泛型占位符>
+
+    //泛型占位语法
+    //基本语法：函数名<泛型占位符>(参数列表)
+
+    //注意：泛型占位符可以有多个，用逗号分开
+    #endregion
+
+    #region 知识点三 泛型类和接口
+    class Test<T>
+    {
+        public T value;
+    }
+    
+    class Test2<T1, T2, K, M, L>
+    {
+        public T1 value1;
+        public T2 value2;
+        public K value3;
+        public M value4;
+        public L value5;
+    }
+
+    interface TestInterface<T>
+    {
+        T value
+        {
+            get
+            {
+                return value;
+            }
+            set
+            {
+                this.value = value;
+            }
+        }
+    }
+
+    class Test4 : TestInterface<int>
+    {
+        //接口实现
+    }
+    #endregion
+
+    #region 知识点四 泛型方法
+    class Test5
+    {
+        public void TestFun<T>(T value)
+        {
+            Console.WriteLine(value);
+        }
+        public void TestFun<T>()
+        {
+            //用泛型类型做逻辑处理
+            T t = default(T);//
+        }
+
+        public T TestFun<T>(string v)
+        {
+            return default(T);
+        }
+
+        public void TestFun<T, K, M>(T t,K k,M m)
+        {
+
+        }
+    }
+    class Test5<T>//泛型类和普通类即使只是多加一个泛型也是两个类
+    {
+        public T value;
+
+        //下面这个不是泛型方法，因为T是泛型类声明时指定的
+        //我们就不能再手动指定类型了
+        public void TestFun(T t)
+        {
+
+        }
+        public void TestFun<K>(K k)
+        {
+
+        }
+    }
+    #endregion
+
+    #region 知识点五 泛型的作用
+    //1.不同类型的对象的相同逻辑处理可以用泛型
+    //2.使用泛型可以一定程度上避免装箱拆箱
+    //举例：优化ArrayList
+    class ArrayList<T>
+    {
+        private T[] array;//实现它的增删查改
+    }
+    #endregion
+
+
+
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Test<int> t1 = new Test<int>();
+            t1.value = 10;
+            Console.WriteLine(t1.value);
+
+            Test<string> t2 = new Test<string>();
+            t2.value = "test";
+            Console.WriteLine(t2.value);
+
+            Test5 t3 = new Test5();
+            t3.TestFun<string>("123");
+
+            Test5<int> t4 = new Test5<int>();
+            //t4.TestFun<("123");//不能是string了因为声明时是int
+            t4.TestFun<string>("123");
+            t4.TestFun<float>(1.23f);
+        }
+    }
+}
@@ -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>
@@ -0,0 +1,33 @@
+namespace Lesson5_泛型练习
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Console.WriteLine("Hello, World!");
+            Console.WriteLine(InputType<int>());
+            Console.WriteLine(InputType<float>());
+            Console.WriteLine(InputType<double>());
+            Console.WriteLine(InputType<string>());
+            Console.WriteLine(InputType<decimal>());
+
+        }
+        public static string InputType<T>()
+        {
+            if (typeof(T) == typeof(int))
+            {
+                return string.Format("{0},{1}字节", "整形", sizeof(int));
+            }else if (typeof(T) == typeof(float))
+            {
+                return string.Format("{0},{1}字节", "单精度浮点数", sizeof(float));
+            }else if (typeof(T) == typeof(double))
+            {
+                return string.Format("{0},{1}字节", "双精度浮点数", sizeof(double));
+            }else if (typeof(T) == typeof(string))
+            {
+                return string.Format("{0},{1}字节", "字符串", "不定长");
+            }
+            return "其他类型";
+        }
+    }
+}