Create proof-of-concept

AvastRecruitmentPrimeMultiplication.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30128.74
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UnitTestProject1", "UnitTestProject1\UnitTestProject1.csproj", "{2C1DA99E-D388-484C-A81B-07C14664C950}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{2C1DA99E-D388-484C-A81B-07C14664C950}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2C1DA99E-D388-484C-A81B-07C14664C950}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2C1DA99E-D388-484C-A81B-07C14664C950}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2C1DA99E-D388-484C-A81B-07C14664C950}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {3F350A24-D07F-4172-8EE7-25461400CE51}
+	EndGlobalSection
+EndGlobal

UnitTestProject1/Extensions.cs

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+namespace UnitTestProject1
+{
+    using System.Collections.Generic;
+
+    internal static class Extensions
+    {
+        internal static IEnumerable<int> Primes(this int count)
+        {
+            var n = 1; // will start at two anyway
+
+            // Decrement count until zero
+            while (count-- > 0)
+            {
+                // Increment number until prime
+                while (!(++n).IsPrime())
+                {
+                }
+
+                yield return n;
+            }
+        }
+
+        internal static bool IsPrime(this int n)
+        {
+            var i = 2; // one divides all
+
+            // Check up to square root of n
+            while (i * i <= n)
+            {
+                // Check if divides and increment
+                if (n % i++ == 0)
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+    }
+
+}

UnitTestProject1/UnitTest1.cs

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+namespace UnitTestProject1
+{
+    using System;
+    using System.Globalization;
+    using System.Linq;
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class UnitTest1
+    {
+        [TestMethod]
+        public void ProofOfConcept()
+        {
+            const int n = 10;
+            var primes = n.Primes().ToArray();
+
+            var largestPrime = primes.Last();
+            var largestMultiple = largestPrime * largestPrime;
+            var cellWidth = largestMultiple.ToString(CultureInfo.InvariantCulture).Length + 1;
+            var format = $"{{0, {cellWidth}}}"; // Padding composite formatting string
+
+            // Header row
+            WriteRow();
+
+            // Body
+            foreach (var prime in primes)
+            {
+                WriteRow(prime);
+            }
+
+            void WriteRow(int? rowHeader = null)
+            {
+                // Header column
+                WriteCell(rowHeader);
+
+                foreach (var prime in primes)
+                {
+                    WriteCell(prime, rowHeader ?? 1);
+                }
+
+                Console.WriteLine(); // LF
+            }
+
+            void WriteCell(int? prime1 = null, int? prime2 = 1)
+            {
+                Console.Write(format, prime1 * prime2);
+            }
+        }
+    }
+}

UnitTestProject1/UnitTestProject1.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.6.1" />
+    <PackageReference Include="MSTest.TestAdapter" Version="2.1.2" />
+    <PackageReference Include="MSTest.TestFramework" Version="2.1.2" />
+  </ItemGroup>
+
+</Project>