diff --git a/ConsoleApp1.sln b/ConsoleApp1.sln
new file mode 100644
index 0000000000000000000000000000000000000000..9f9185ba0dd10a2576675456fab6b46119ac8b6a
--- /dev/null
+++ b/ConsoleApp1.sln
@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.7.34031.279
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ConsoleApp1", "ConsoleApp1.csproj", "{CE2106D1-549D-4AAF-B37D-C12B806EDD63}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{CE2106D1-549D-4AAF-B37D-C12B806EDD63}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{CE2106D1-549D-4AAF-B37D-C12B806EDD63}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{CE2106D1-549D-4AAF-B37D-C12B806EDD63}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{CE2106D1-549D-4AAF-B37D-C12B806EDD63}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {022CE94C-C641-4773-8B12-57921299962D}
+	EndGlobalSection
+EndGlobal
diff --git a/Program.cs b/Program.cs
new file mode 100644
index 0000000000000000000000000000000000000000..c448b490c1b4e3a3fd09f54c09bbb3be521935b0
--- /dev/null
+++ b/Program.cs
@@ -0,0 +1,2 @@
+
+Console.WriteLine("Hello, World!");
diff --git "a/\344\270\273\345\207\275\346\225\260.cs" "b/\344\270\273\345\207\275\346\225\260.cs"
new file mode 100644
index 0000000000000000000000000000000000000000..61c0407f5af08ba654c325cd4d1d0742d6d786da
--- /dev/null
+++ "b/\344\270\273\345\207\275\346\225\260.cs"
@@ -0,0 +1,205 @@
+using System;
+using System.Text.RegularExpressions;
+
+class Utility
+{
+    // 交换两个变量
+    public static void Swap(ref int firstNumber, ref int secondNumber)
+    {
+        firstNumber = firstNumber + secondNumber;
+        secondNumber = firstNumber - secondNumber;
+        firstNumber = firstNumber - secondNumber;
+    }
+
+    // 计算加、减、乘、除
+    public static void Calculate(int firstNumber, int secondNumber, out int sum, out int difference, out int product, out int quotient)
+    {
+        sum = firstNumber + secondNumber;
+        difference = firstNumber - secondNumber;
+        product = firstNumber * secondNumber;
+        quotient = firstNumber / secondNumber;
+    }
+
+    // 计算任意多个数的最大值
+    public static int Max(params int[] numbers)
+    {
+        int maxValue = numbers[0];
+        foreach (int number in numbers)
+        {
+            if (number > maxValue) maxValue = number;
+        }
+        return maxValue;
+    }
+
+    // 冒泡排序
+    public static void Sort(int[] array)
+    {
+        int length = array.Length;
+        for (int i = 0; i < length - 1; i++)
+        {
+            for (int j = 0; j < length - i - 1; j++)
+            {
+                if (array[j] > array[j + 1])
+                {
+                    int temp = array[j];
+                    array[j] = array[j + 1];
+                    array[j + 1] = temp;
+                }
+            }
+        }
+    }
+
+    // 格式化字符串
+    public static string Format(string input)
+    {
+        input = input.Trim();
+        input = Regex.Replace(input, @"\s+", " ");
+        return input;
+    }
+}
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        // 1. 交换两个变量
+        Console.WriteLine($"第一题，输入回车继续");
+        string input = Console.ReadLine();
+        int number1 = 10, number2 = 20;
+        Console.WriteLine($"交换前: number1 = {number1}, number2 = {number2}");
+        number1 = number1 + number2;
+        number2 = number1 - number2;
+        number1 = number1 - number2;
+        Console.WriteLine($"交换后: number1 = {number1}, number2 = {number2}");
+
+        // 2. 使用 ref 方法交换
+        Console.WriteLine($"第二题，输入回车继续");
+        input = Console.ReadLine();
+        Console.WriteLine($"交换前: number1 = {number1}, number2 = {number2}");
+        Utility.Swap(ref number1, ref number2);
+        Console.WriteLine($"交换后: number1 = {number1}, number2 = {number2}");
+
+        // 3. 计算加、减、乘、除
+        Console.WriteLine($"第三题，输入两个数字用回车分开");
+        int sum, difference, product, quotient;
+        int firstNumber = int.Parse(Console.ReadLine());
+        int secondNumber = int.Parse(Console.ReadLine());
+        Utility.Calculate(firstNumber, secondNumber, out sum, out difference, out product, out quotient);
+        Console.WriteLine($"计算: 和 = {sum}, 差 = {difference}, 积 = {product}, 商 = {quotient}");
+
+        // 4. 计算任意多个数的最大值
+        Console.WriteLine($"第四题");
+        Console.WriteLine("请输入五个整数，用回车分隔：");
+        int num1 = int.Parse(Console.ReadLine());
+        int num2 = int.Parse(Console.ReadLine());
+        int num3 = int.Parse(Console.ReadLine());
+        int num4 = int.Parse(Console.ReadLine());
+        int num5 = int.Parse(Console.ReadLine());
+        int maxValue = Utility.Max(num1, num2, num3, num4, num5);
+        Console.WriteLine($"最大值: {maxValue}");
+
+        // 5. 斐波那契数列前20项的和
+        Console.WriteLine($"第五题，输入回车继续");
+        input = Console.ReadLine();
+        int a = 0, b = 1, sumFibonacci = 0;
+        for (int i = 0; i < 20; i++)
+        {
+            sumFibonacci += a;
+            int temp = a;
+            a = b;
+            b = temp + b;
+        }
+        Console.WriteLine($"斐波那契数列前20项的和: {sumFibonacci}");
+
+        // 6. 打印杨辉三角形
+        Console.WriteLine($"第六题，输入回车继续");
+        input = Console.ReadLine();
+        Console.WriteLine("杨辉三角形:");
+        for (int i = 0; i < 10; i++)
+        {
+            int value = 1;
+            for (int j = 0; j <= i; j++)
+            {
+                Console.Write(value + " ");
+                value = value * (i - j) / (j + 1);
+            }
+            Console.WriteLine();
+        }
+
+        // 7. 冒泡排序
+        Console.WriteLine($"第七题，输入回车继续");
+        input = Console.ReadLine();
+        int[] array = { 20, 16, 78, 61, 12, 99, 57, 34, 8 };
+        Utility.Sort(array);
+        Console.WriteLine("冒泡排序结果: " + string.Join(", ", array));
+
+        // 8. 统计字符串中“咳嗽”的出现次数及索引位置
+        Console.WriteLine($"第八题，输入回车继续");
+        input = Console.ReadLine();
+        string text = "患者：“大夫，我咳嗽得很重。”     大夫：“你多大年记？”     患者：“七十五岁。”     大夫：“二十岁咳嗽吗”患者：“不咳嗽。”     大夫：“四十岁时咳嗽吗？”     患者：“也不咳嗽。”     大夫：“那现在不咳嗽，还要等到什么时咳嗽？”";
+        string keyword = "咳嗽";
+        int count = 0;
+        int index = -1;
+
+        while ((index = text.IndexOf(keyword, index + 1)) != -1)
+        {
+            count++;
+            Console.WriteLine($"Found '{keyword}' at index: {index}");
+        }
+
+        Console.WriteLine($"Total occurrences of '{keyword}': {count}");
+
+        // 9. 从日期字符串中提取年、月、日
+        Console.WriteLine($"第九题，输入回车继续");
+        input = Console.ReadLine();
+        string dateStr = "2020年10月1日";
+        int year = int.Parse(dateStr.Substring(0, 4));
+        int month = int.Parse(dateStr.Substring(5, 2));
+        int day = int.Parse(dateStr.Substring(8, 1));
+        Console.WriteLine($"Year: {year}, Month: {month}, Day: {day}");
+
+        // 10. 格式化字符串
+        Console.WriteLine($"第十题，输入回车继续");
+        input = Console.ReadLine();
+        string inputStr = "  Hello   World  !   你好    世界 ！ ";
+        string formattedStr = Utility.Format(inputStr);
+        Console.WriteLine($"格式化后的字符串: \"{formattedStr}\"");
+
+        // 11. 猜拳游戏
+        Console.WriteLine($"第十一题，输入回车继续");
+        input = Console.ReadLine();
+        Random random = new Random();
+        string[] choices = { "石头", "剪刀", "布" };
+
+        while (true)
+        {
+            Console.WriteLine("请输入你的选择（石头、剪刀、布）：");
+            string playerChoice = Console.ReadLine();
+            int computerChoice = random.Next(0, 3);
+
+            Console.WriteLine($"你选择了：{playerChoice}");
+            Console.WriteLine($"电脑选择了：{choices[computerChoice]}");
+
+            if (playerChoice == choices[computerChoice])
+            {
+                Console.WriteLine("平局！");
+            }
+            else if ((playerChoice == "石头" && choices[computerChoice] == "剪刀") ||
+                     (playerChoice == "剪刀" && choices[computerChoice] == "布") ||
+                     (playerChoice == "布" && choices[computerChoice] == "石头"))
+            {
+                Console.WriteLine("你赢了！");
+            }
+            else
+            {
+                Console.WriteLine("你输了！");
+            }
+
+            Console.WriteLine("再来一局？(y/n)");
+            if (Console.ReadLine().ToLower() != "y")
+            {
+                break;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git "a/\351\202\223\347\232\223\346\226\207/\345\256\236\351\252\2141.cs" "b/\351\202\223\347\232\223\346\226\207/\345\256\236\351\252\2141.cs"
new file mode 100644
index 0000000000000000000000000000000000000000..15d0f914f00ef7e88ac63cfaec997d16b4d9cf97
--- /dev/null
+++ "b/\351\202\223\347\232\223\346\226\207/\345\256\236\351\252\2141.cs"
@@ -0,0 +1,208 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Xml.Serialization;
+class program
+{
+    static void Test01(){
+        int x=int.Parse(Console.ReadLine());
+        int y=int.Parse(Console.ReadLine());
+        x = x + y;
+        y = x - y;
+        x = x - y;
+
+        Console.WriteLine("x={0},y={1}",x,y);
+}
+    static void Test02(ref int x,ref int y)
+    {
+        x = x + y;
+        y = x - y;
+        x = x - y;
+    }
+    static void Test03(int a, int b, out int sum, out int difference, out int product, out double quotient)
+    {
+        sum = a + b; 
+        difference = a - b; 
+        product = a * b;
+        if (b != 0) 
+        { quotient = (double)a / b;  }
+        else { quotient = double.NaN; }
+    }
+
+    static void Test04()
+    {
+     
+        int max = FindMax(10, 20, 5, 30, 15);
+
+        
+        Console.WriteLine("Test04 - 最大值: {0}", max);
+    }
+
+    
+    static int FindMax(params int[] numbers)
+    {
+        if (numbers.Length == 0)
+        {
+            Console.WriteLine("至少需要提供一个参数");
+        }
+
+        int max = numbers[0];
+        foreach (int num in numbers)
+        {
+            if (num > max)
+            {
+                max = num;
+            }
+        }
+        return max;
+    }
+    static void Test05()
+    {
+        
+        int sum = fbnq(20);
+
+        
+        Console.WriteLine("Test05 - 斐波那契数列前20项的和: {0}", sum);
+    }
+
+    
+    static int fbnq(int n) { 
+    
+        if (n <= 0)
+        {
+            throw new ArgumentException("n 必须大于 0");
+        }
+
+        int a = 0, b = 1, sum = 0;
+
+        for (int i = 0; i < n; i++)
+        {
+            sum += a;
+            int temp = a;
+            a = b;
+            b = temp + b;
+        }
+
+        return sum;
+    }
+    static void  Test06()
+    {
+        int N = 10;
+        int[,] arr = new int[N,N];
+        for (int i = 0; i < N; i++)
+        {
+            arr[i, 0] = 1;
+            arr[i, i] = 1;
+        }
+        for (int i = 2; i < N; i++)
+        {
+            for (int j = 1; j < i; j++)
+            {
+                arr[i, j] = arr[i - 1, j - 1] + arr[i - 1, j];
+            }
+        }
+        for (int i = 0; i < N; i++)
+        {
+            
+            for (int j = 0; j < N - i - 1; j++)
+            {
+                Console.Write("  ");
+            }
+
+           
+            for (int j = 0; j <= i; j++)
+            {
+                Console.Write(arr[i, j] + "  ");
+            }
+
+            
+            Console.WriteLine();
+        }
+    }
+    static void My_sort(int[] arr,int l,int r)
+    {  if (l >= r) return;
+        int x=arr[(l+r)/2];
+        int i = l - 1;
+        int j = r + 1;
+        while (i<j)
+        {
+            do i++; while (arr[i] < x);
+            do j--;while (arr[j] > x);
+            if (i < j) Test02(ref arr[i], ref arr[j]);
+        }
+        My_sort(arr,l,j);
+        My_sort(arr,j+1,r);
+    }
+    static void Test07()
+    {
+        int[] arr = { 20, 16, 78, 61, 12, 99, 57, 34, 8 };
+        My_sort(arr,0,8);
+        foreach(int i in arr)
+        {
+            Console.WriteLine(i);
+        }
+    }
+    static void Test08()
+    {
+        List<string>arr=new List<string>();
+        List<int>position = new List<int>();
+        arr.Add("患者：“大夫，我咳嗽得很重。”     大夫：“你多大年记？”     患者：“七十五岁。”     大夫：“二十岁咳嗽吗”患者：“不咳嗽。”     大夫：“四十岁时咳嗽吗？”     患者：“也不咳嗽。”     大夫：“那现在不咳嗽，还要等到什么时咳嗽？");
+        string keyword = "咳嗽";
+         int index = 0;
+        while ((index = arr[0].IndexOf(keyword,index)) != -1)
+        {
+            position.Add(index);
+            index += keyword.Length;
+        }
+        Console.WriteLine($"关键字 '{keyword}' 出现了 {position.Count} 次。");
+        Console.WriteLine("出现的位置如下：");
+        foreach (int pos in position)
+        {
+            Console.WriteLine($"位置: {pos}");
+        }
+    }
+    static void Test09()
+    {
+        string dateStr = "2020年10月1日";
+        int yearIndex = dateStr.IndexOf("年");
+        int monthIndex = dateStr.IndexOf("月");
+        int dayIndex = dateStr.IndexOf("日");
+        string year = dateStr.Substring(0, yearIndex);
+        string month = dateStr.Substring(yearIndex + 1, monthIndex - yearIndex - 1);
+        string day = dateStr.Substring(monthIndex + 1, dayIndex - monthIndex - 1);
+        Console.WriteLine($"年: {year}");
+        Console.WriteLine($"月: {month}");
+        Console.WriteLine($"日: {day}");
+    }
+    static void Test10()
+    {
+        string input = "  Hello   World  !   你好    世界 ！ ";
+        string trimmed = input.Trim();
+        StringBuilder result = new StringBuilder();
+        bool pre = false;
+
+        foreach (char c in trimmed)
+        {
+            if (c == ' ')
+            {
+                if (!pre)
+                {
+                    result.Append(c);
+                    pre = true;
+                }
+            }
+            else
+            {
+                result.Append(c);
+                pre = false;
+            }
+        }
+        Console.WriteLine($"原始字符串: \"{input}\"");
+        Console.WriteLine($"处理后的字符串: \"{result.ToString()}\"");
+    }
+
+    static void Main(string[] args)
+    {
+      Test08();
+    }
+}