add C#/thititongumpun (#194)

C#/thititongumpun/Program.cs

@@ -0,0 +1,28 @@
+using System.Globalization;
+
+class Program
+{
+    private static void Main(string[] args)
+    {
+        {
+            string input = "";
+
+            while (input.ToLower() != "coffee")
+            {
+                Console.WriteLine("Please input Coffee or COFFEE: ");
+                input = Console.ReadLine()!;
+                if (input.ToLower() == "coffee")
+                {
+                    Console.WriteLine(ToTitleCase("code"));
+                }
+            }
+            Environment.Exit(0);
+        }
+    }
+
+    private static string ToTitleCase(string str)
+    {
+        var textInfo = new CultureInfo("en-US", false).TextInfo;
+        return textInfo.ToTitleCase(str);
+    }
+}

C#/thititongumpun/thititongumpun.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>