build and bug fix

ExtensionTypesCsharp13/Program.cs

@@ -1,6 +1,8 @@
 // Extension types
 // https://github.com/dotnet/csharplang/blob/main/proposals/extensions.md
 
+Console.WriteLine("Test 1");
+
 // C# 3.0 Version
 public static class StringExtensionsCsharp3
 {
@@ -11,6 +13,7 @@ public static bool IsNotNullOrEmpty(this string text)
 }
 
 // C# 13 Version
+/*
 implicit extension StringExtensionsCsharp13 for string
 {
     public bool IsNotNullOrEmptyV1()
@@ -34,3 +37,4 @@ public bool this[int index]
     
     static ulong Mask(int index) => `ul << index;
 }
+*/

NewLINQMethodsCsharp13/NewLINQMethodsCsharp13.csproj

@@ -6,6 +6,7 @@
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <LangVersion>preview</LangVersion>
+    <StartupObject>NewLINQMethodsCsharp13.Program</StartupObject>
   </PropertyGroup>
 
 </Project>

NewLINQMethodsCsharp13/Program.cs

@@ -1,16 +1,24 @@
-public record Person(string name);
-
-var persons = new List<Person>() { new("p1"), new("p2") };
-
-// Using a for loop
-for (int i = 0; i < persons.Count; i++)
+namespace NewLINQMethodsCsharp13
 {
-    var person = persons[i];
-    Console.WriteLine($"Index: {i}, Person:{person}");
-}
+    public record Person(string name);
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            var persons = new List<Person>() { new("p1"), new("p2") };
 
-// Using the new .NET 9 Index method.
-foreach ((int index, Person person) in persons.Index())
-{
-    Console.WriteLine($"Index: {index}, Person:{person}");
+            // Using a for loop
+            for (int i = 0; i < persons.Count; i++)
+            {
+                var person = persons[i];
+                Console.WriteLine($"Index: {i}, Person:{person}");
+            }
+
+            // Using the new .NET 9 Index method.
+            foreach ((int index, Person person) in persons.Index())
+            {
+                Console.WriteLine($"Index: {index}, Person:{person}");
+            }
+        }
+    }
 }

TheLockStatement/Program.cs

@@ -13,6 +13,7 @@
 // What is the difference between Task.Run() and Task.Factory.StartNew()
 // https://stackoverflow.com/questions/38423472/what-is-the-difference-between-task-run-and-task-factory-startnew
 
+#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
 Task.Factory.StartNew(() =>
 {
     Singleton instance2 = Singleton.Instance;
@@ -30,11 +31,12 @@
         Console.WriteLine(instance2.CurrentDateTime);
     }, TaskCreationOptions.AttachedToParent).Start();
 });
+#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
 
 
 public class Singleton
 {
-    private readonly System.Threading.Lock _lock = new();
+    private static readonly System.Threading.Lock _lock = new();
     private static Singleton instance = null;
     public DateTime CurrentDateTime => _currentDateTime;
     private DateTime _currentDateTime;
@@ -43,7 +45,7 @@ public static Singleton Instance
     {
         get
         {
-            if (_lock)
+            lock (_lock)
             {
                 // Logical patterns Csharp-9
                 // https://devblogs.microsoft.com/dotnet/c-9-0-on-the-record/#logical-patterns