添加Lesson1，ArrayList

2025-10-10 09:39:57 +08:00
parent 341fa3a006
commit 114536061f
6 changed files with 227 additions and 1 deletions
@@ -1,10 +1,14 @@

 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 17
-VisualStudioVersion = 17.14.36202.13 d17.14
+VisualStudioVersion = 17.14.36202.13
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "test", "test\test.csproj", "{5B032C55-6E02-4EA9-BE52-083A6DA91295}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson1_ArrayList", "Lesson1_ArrayList\Lesson1_ArrayList.csproj", "{A3FB97E5-BFB8-41F5-AA91-79C16EC75513}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson1_ArrayList练习题", "Lesson1_ArrayList练习题\Lesson1_ArrayList练习题.csproj", "{B9F9E174-21EA-40E7-A139-58FFD3448023}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -15,6 +19,14 @@ Global
 		{5B032C55-6E02-4EA9-BE52-083A6DA91295}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{5B032C55-6E02-4EA9-BE52-083A6DA91295}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{5B032C55-6E02-4EA9-BE52-083A6DA91295}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A3FB97E5-BFB8-41F5-AA91-79C16EC75513}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A3FB97E5-BFB8-41F5-AA91-79C16EC75513}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A3FB97E5-BFB8-41F5-AA91-79C16EC75513}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A3FB97E5-BFB8-41F5-AA91-79C16EC75513}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B9F9E174-21EA-40E7-A139-58FFD3448023}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B9F9E174-21EA-40E7-A139-58FFD3448023}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B9F9E174-21EA-40E7-A139-58FFD3448023}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B9F9E174-21EA-40E7-A139-58FFD3448023}.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 +1,86 @@
+using System.Collections;
+
+namespace Lesson1_ArrayList
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            #region 练习题回归
+            //C#核心中 索引器的练习题
+            //自定义一个整形数组类，该类中有一个整形数组变量
+            //为他封装增删查改的方法
+            #endregion
+
+            #region 知识点一 ArrayList的本质
+            //ArrayList是c#为我们封装好的类
+            //本质是一个Object类型的数组
+            //ArrayList可以帮我们实现增删改查等功能
+            #endregion
+
+            #region 知识点二 声明
+            //注意：使用ArrayList需要引入命名空间 using System.Collections;
+            ArrayList arrayList = new ArrayList();
+            #endregion
+            ///可以用F12进ArrayList中查看方法或去微软官方文档查看
+
+
+            #region 知识点三 增删改查
+            //增
+            arrayList.Add(1.2f);
+            arrayList.Add("123");
+            arrayList.Add(new Object());
+            arrayList.Add(true);
+            //插入
+            arrayList.Insert(0, "插入的元素");//在指定索引位置插入元素，原来该位置及其后面的元素依次后移
+
+            arrayList.AddRange(new int[] { 1, 2, 3, 4, 5 });//一次性添加多个元素
+            //删
+            arrayList.Remove("123");//移除指定元素，如果有多个相同元素，只移除第一个
+            arrayList.RemoveAt(0);//移除指定索引位置的元素
+            arrayList.RemoveRange(0, 2);//移除从指定索引位置开始的指定个数的元素
+            arrayList.Clear();//清空所有元素
+            //改
+            arrayList[1] = 4;
+            //查
+            Console.WriteLine(arrayList[0]);
+            if (arrayList.Contains("123"))
+            {
+                //如果包含指定元素执行的代码
+            }
+            //正向查找指定的元素，返回索引位置，如果没有找到返回-1
+            int index = arrayList.IndexOf(3);
+            Console.WriteLine(index);
+            //反向查找指定的元素，返回索引位置，如果没有找到返回-1
+            int lastIndex = arrayList.LastIndexOf(3);
+            Console.WriteLine(lastIndex);
+            #region 遍历
+            Console.WriteLine(arrayList.Count);//获取元素个数(长度)
+            Console.WriteLine(arrayList.Capacity);//获取ArrayList的容量(用于以后避免产生过多垃圾)
+            for (int i = 0; i < arrayList.Count; i++)
+            {
+                Console.WriteLine(arrayList[i]);
+            }
+            //迭代器遍历
+            foreach (var item in arrayList)//有个var类型临时变量item来接每次遍历到的元素
+            {
+                Console.WriteLine(item);
+            }
+            #endregion
+
+            #endregion
+
+            #region 知识点四 装箱拆箱
+            //ArrayList存储的是Object类型的元素
+            //所以Object类型的数组存储的是值类型时会发生装箱拆箱
+            //装箱：值类型转换为引用类型的过程
+            //拆箱：引用类型转换为值类型的过程
+            //所以ArrayList存储值类型时会影响性能尽量少用
+            int i = 1;
+            arrayList.Add(i);//发生装箱
+            int j = (int)arrayList[0];//发生拆箱
+            #endregion
+
+        }
+    }
+}
@@ -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 +1,85 @@
+using System.Collections;
+
+namespace Lesson1_ArrayList练习题
+{
+    class Backpack
+    {
+        ArrayList stuff;
+        int money;
+        public Backpack() 
+        {
+            money = 0;
+            stuff = new ArrayList();
+        }
+        public Backpack(int money)
+        {
+            stuff = new ArrayList();
+            this.money = money;
+        }
+        public void ShowBackPack()
+        {
+            Console.WriteLine("背包物品有：");
+            for (int i = 0; i < stuff.Count; i++)
+            {
+                if (i + 1 != stuff.Count)
+                {
+                    Console.Write(stuff[i] + "、");
+                }
+                else
+                {
+                    Console.WriteLine(stuff[i]);
+                }
+            }
+        }
+        public void BuyStuff(Object obj,int cost) 
+        {
+            if(cost > money)
+            {
+                Console.WriteLine("余额不足");
+            }
+            else
+            {
+                stuff.Add(obj);
+                money -= cost;
+                Console.WriteLine("成功购买物品：" + obj);
+            }
+        }
+        public void SoldStuff(object obj,int earned)
+        {
+            if (stuff.Contains(obj))
+            {
+                stuff.Remove(obj);
+                money += earned;
+                Console.WriteLine("成功出售物品：" + obj);
+            }
+            else
+            {
+                Console.WriteLine("没有该物品，无法出售：" + obj);
+            }
+        }
+        public void ShowMoney()
+        {
+            Console.WriteLine("当前余额：" + money);
+        }
+    }
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            Backpack b1= new Backpack();
+            Backpack b2 = new Backpack(100);
+            b1.ShowBackPack();
+            b2.ShowBackPack();
+            b1.BuyStuff("sth1", 50);
+            b2.BuyStuff("sth2", 50);
+            b1.ShowBackPack();
+            b2.ShowBackPack();
+            b1.SoldStuff("sth1", 25);
+            b2.SoldStuff("sth2", 25);
+            b1.ShowBackPack();
+            b2.ShowBackPack();
+            b1.ShowMoney();
+            b2.ShowMoney();
+        }
+    }
+}
@@ -6,5 +6,28 @@
        {
            Console.WriteLine("Hello, World!");
        }
+        #region 知识点一 
+        #endregion
+
+        #region 知识点二 
+        #endregion
+
+        #region 知识点三 
+        #endregion
+
+        #region 知识点四 
+        #endregion
+
+        #region 知识点五 
+        #endregion
+
+        #region 知识点六 
+        #endregion
+
+        #region 知识点七 
+        #endregion
+
+        #region 知识点八 
+        #endregion
    }
 }