dotnet 7 list patterns sample

Author: christiannagel

5_More/CSharp/VirtualInterfaceMembersAndListPatterns/ListPatterns.csproj

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

5_More/CSharp/VirtualInterfaceMembersAndListPatterns/ListPatterns.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.4.32916.344
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ListPatterns", "ListPatterns.csproj", "{3134C4B4-0C1B-49F8-A513-6888046A328C}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{3134C4B4-0C1B-49F8-A513-6888046A328C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3134C4B4-0C1B-49F8-A513-6888046A328C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3134C4B4-0C1B-49F8-A513-6888046A328C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3134C4B4-0C1B-49F8-A513-6888046A328C}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {F02BD99B-15C7-4D7F-946F-7CB6947228C0}
+	EndGlobalSection
+EndGlobal

5_More/CSharp/VirtualInterfaceMembersAndListPatterns/Program.cs

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+using System.Numerics;
+
+int[] list1 = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+double[] list2 = { 1, 2, 3, 4.4, 5, 6, 7, 8, 9 };
+
+var result = AddAll1(list1);
+Console.WriteLine(result);
+
+var result2 = AddAll2(list2);
+Console.WriteLine(result2);
+
+var result3 = AddAll3(list2);
+Console.WriteLine(result3);
+
+var result4 = AddAll4(list2.AsSpan());
+Console.WriteLine(result4);
+
+int AddAll1(int[] values)
+{
+    int result = 0;
+    foreach (var value in values)
+    {
+        result += value;
+    }
+    return result;
+}
+
+// with INumber<T> constraint!
+T AddAll2<T>(T[] values) where T : INumber<T>
+{
+    T result = T.Zero;
+    foreach (var value in values)
+    {
+        result += value;
+    }
+    return result;
+}
+
+// with list pattern matching - and INumber<T> constraint
+T AddAll3<T>(T[] values) where T : INumber<T> =>
+    values switch
+    {
+        [] => T.Zero,
+        [var first, .. var rest] => first + AddAll3(rest),
+    };
+
+T AddAll4<T>(Span<T> values) where T : INumber<T> =>
+    values switch
+    {
+        [] => T.Zero,
+        [var first, .. var rest] => first + AddAll4(rest),
+    };