Cash Register Calculate Change and Special Rule Divide by 3

.gitignore

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+################################################################################
+# This .gitignore file was automatically created by Microsoft(R) Visual Studio.
+################################################################################
+
+/.vs
+/CashRegister/.vs/CashRegister
+/CashRegister/bin/Debug/net9.0
+/CashRegister/obj

CashRegister/CashRegister.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Update="denomination.csv">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+    <None Update="divisor.txt">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+    <None Update="transactions.csv">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>

CashRegister/CashRegister.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.14.36915.13 d17.14
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CashRegister", "CashRegister.csproj", "{CE3E71EF-2232-442D-8ED6-D88B79016264}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{CE3E71EF-2232-442D-8ED6-D88B79016264}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{CE3E71EF-2232-442D-8ED6-D88B79016264}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{CE3E71EF-2232-442D-8ED6-D88B79016264}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{CE3E71EF-2232-442D-8ED6-D88B79016264}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {07EBE533-1856-402A-9985-7D4BFE493F5A}
+	EndGlobalSection
+EndGlobal

CashRegister/Program.cs

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+class Program
+{
+
+  static void Main()
+  {
+    // Inputs
+    string sourceFile = "transactions.csv";
+    string destinationFile = "output.txt";
+    string denominationsFile = "denomination.csv";
+    string divisorFile = "divisor.txt";
+
+    try
+    {
+
+      // Get Data
+      int divisor = int.Parse(File.ReadAllText(divisorFile));
+
+      var transactions = GetFileData(sourceFile, divisor);
+
+      var denominations = GetDenominations(denominationsFile);
+
+      // Parse Data
+      var results = ParseTransaction(denominations, transactions);
+
+      // Write results
+      WriteFileData(destinationFile, results);
+
+    }
+    catch (Exception ex)
+    {
+      System.Console.WriteLine("Error: ", ex);
+    }
+
+  }
+
+  private static List<string> ParseTransaction(List<Denomination> denominations, List<Transaction> transactions)
+  {
+    var parsedTransactions = new List<string>();
+
+    foreach (var transaction in transactions)
+    {
+      try
+      {
+        // Per Transaction Rules can be applied here
+
+        parsedTransactions.Add(
+          GetChange(denominations, transaction.amountOwed, transaction.amountPaid, transaction.divisibleByInput)
+        );
+
+      }
+      catch (Exception)
+      {
+        // skip invalid transactions; no requirements specified;       
+      }
+    }
+
+    return parsedTransactions;
+  }
+
+
+  #region File Operations
+
+
+  private static List<Transaction> GetFileData(string sourceFile, int divisor)
+  {
+    if (File.Exists(sourceFile) == false)
+    {
+      throw new FileNotFoundException("Source file not found", sourceFile);
+    }
+
+    // File Format: Amount Owed, Amount Paid
+    return File.ReadLines(sourceFile)
+        .Select(line =>
+        {
+          var parts = line.Split(',');
+
+          return new Transaction
+          {
+            amountOwed = decimal.Parse(parts[0]),
+            amountPaid = decimal.Parse(parts[1]),
+            divisibleByInput = (int)(decimal.Parse(parts[0]) * 100) % divisor == 0
+          };
+        })
+    .ToList();
+  }
+
+  private static void WriteFileData(string destinationFile, List<string> results)
+  {
+    File.WriteAllLines(destinationFile, results);
+  }
+
+  /// <summary>
+  /// Gets the List of currencies used
+  /// </summary>
+  /// <param name="sourceFile"></param>
+  /// <returns></returns>
+  /// <exception cref="FileNotFoundException"></exception>
+  private static List<Denomination> GetDenominations(string sourceFile)
+  {
+    if (File.Exists(sourceFile) == false)
+    {
+      throw new FileNotFoundException("Source file not found", sourceFile);
+    }
+
+    // File Format: decimal value, name of denomination, plural name of denomination
+    return File.ReadLines(sourceFile)
+                         .Select(line =>
+                         {
+                           var parts = line.Split(',');
+
+                           return new Denomination
+                           {
+                             value = decimal.Parse(parts[0]),
+                             name = parts[1],
+                             namePlural = parts[2]
+                           };
+                         })
+    .ToList();
+  }
+
+  #endregion
+
+  #region Calculations
+
+  private static decimal CalculateChange(decimal amountOwed, decimal amountPaid)
+  {
+    return amountPaid - amountOwed;
+  }
+
+  private static string GetChange(List<Denomination> denominations, decimal amountOwed, decimal amountPaid, bool divisibleByThree)
+  {
+    var changeDue = CalculateChange(amountOwed, amountPaid);
+
+    var result = new List<string>();
+
+    var mostDenomination = denominations.OrderByDescending(d => d.value).FirstOrDefault();
+
+    foreach (var denomination in denominations)
+    {
+      var count = Math.Floor(changeDue / denomination.value);
+
+      // Special Rule per Demoniation here
+
+      if (divisibleByThree && denomination.value > 0.01M)
+      {
+        count = GetRandonIntPerDenomination(mostDenomination.value, count);
+      }
+
+      if (count > 0)
+      {
+        result.Add(@$"{count} {(count > 1 ? denomination.namePlural : denomination.name)}");
+        changeDue -= count * denomination.value;
+      }
+    }
+
+    return string.Join(",", result);
+  }
+
+  /// <summary>
+  /// Used the max count in the specific denomination to get a random integer between 0 and that count
+  /// </summary>
+  /// <param name="maxBound"></param>
+  /// <param name="count"></param>
+  /// <returns></returns>
+  private static int GetRandonIntPerDenomination(decimal maxBound, decimal count)
+  {
+    var random = new Random();
+    int upperBound = Math.Min((int)maxBound, (int)count);
+    int lowerBound = 0;
+    return random.Next(lowerBound, upperBound + 1);
+  }
+
+  #endregion
+
+  #region Classes
+
+  public class Transaction
+  {
+    public decimal amountOwed { get; set; } = 0.00M;
+    public decimal amountPaid { get; set; } = 0.00M;
+
+    public bool divisibleByInput { get; set; } = false;
+  }
+
+  public class Denomination
+  {
+    public decimal value { get; set; } = 0.00M;
+    public string name { get; set; } = default!;
+    public string namePlural { get; set; } = default!;
+  }
+
+  #endregion
+
+}

CashRegister/denomination.csv

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+100.00,hundred,hundreds
+50.00,fifty,fifties
+20.00,twenty,tenties
+10.00,ten,tens
+5.00,five,fives
+1.00,dollar,dollars
+0.25,quarter,quarters
+0.10,dime,dimes
+0.05,nickel,nickels
+0.01,penny,pennies

CashRegister/divisor.txt

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+3

CashRegister/transactions.csv

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+2.12,3.00
+1.97,2.00
+3.33,5.00