diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000..ca5d6d4d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,7 @@
+################################################################################
+# This .gitignore file was automatically created by Microsoft(R) Visual Studio.
+################################################################################
+
+/obj/Debug
+/bin/Debug
+/.vs
diff --git a/App.config b/App.config
new file mode 100644
index 00000000..8fc05512
--- /dev/null
+++ b/App.config
@@ -0,0 +1,6 @@
+
+
+
+
+
+
diff --git a/ChangeCalculatorFactory.cs b/ChangeCalculatorFactory.cs
new file mode 100644
index 00000000..236278fb
--- /dev/null
+++ b/ChangeCalculatorFactory.cs
@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SWCashRegister
+{
+ public static class ChangeCalculatorFactory
+ {
+ private static RandomChangeCalculator randomChangeCalculator = new RandomChangeCalculator();
+ private static MinimumChangeCalculator minimumChangeCalculator = new MinimumChangeCalculator();
+
+ public static IChangeCalculator GetChangeCalculator(int changeAmount)
+ {
+ if (changeAmount % 3 == 0)
+ {
+ return randomChangeCalculator;
+ }
+ else
+ {
+ return minimumChangeCalculator;
+ }
+ }
+ }
+}
diff --git a/Currency.cs b/Currency.cs
new file mode 100644
index 00000000..9c24297a
--- /dev/null
+++ b/Currency.cs
@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SWCashRegister
+{
+ public class Currency
+ {
+ public static Currency Hundred { get; } = new Currency("hundred", "hundreds", 10000);
+ public static Currency Fifty { get; } = new Currency("fifty", "fifties", 5000);
+ public static Currency Twenty { get; } = new Currency("twenty", "twenties", 2000);
+ public static Currency Ten { get; } = new Currency("ten", "tens", 1000);
+ public static Currency Five { get; } = new Currency("five", "fives", 500);
+ public static Currency Dollar { get; } = new Currency("dollar", "dollars", 100);
+ public static Currency Quarter { get; } = new Currency("quarter", "quarters", 25);
+ public static Currency Dime { get; } = new Currency("dime", "dimes", 10);
+ public static Currency Nickel { get; } = new Currency("nickel", "nickels", 5);
+ public static Currency Penny { get; } = new Currency("penny", "pennies", 1);
+
+ public static IEnumerable List()
+ {
+ return new[] { Hundred, Fifty, Twenty, Ten, Five, Dollar, Quarter, Dime, Nickel, Penny };
+ }
+
+ private Currency(string name, string plural, int value)
+ {
+ Name = name;
+ Plural = plural;
+ Value = value;
+ }
+
+ public string Name { get; private set; }
+ public string Plural { get; private set; }
+ public int Value { get; private set; }
+ }
+}
diff --git a/Files/input.txt b/Files/input.txt
new file mode 100644
index 00000000..4dbe6515
--- /dev/null
+++ b/Files/input.txt
@@ -0,0 +1,10 @@
+2.12,3.00
+1.97,2.00
+3.33,5.00
+5.00,3.33
+3.33,5.00
+1.97, 2.00
+34, 50
+3.330,5.000
+32.45,42.4
+this,that
\ No newline at end of file
diff --git a/IChangeCalculator.cs b/IChangeCalculator.cs
new file mode 100644
index 00000000..a277f736
--- /dev/null
+++ b/IChangeCalculator.cs
@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SWCashRegister
+{
+ public interface IChangeCalculator
+ {
+ IList<(Currency, int)> GetChange(int changeAmount);
+ }
+}
diff --git a/MinimumChangeCalculator.cs b/MinimumChangeCalculator.cs
new file mode 100644
index 00000000..376c3233
--- /dev/null
+++ b/MinimumChangeCalculator.cs
@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SWCashRegister
+{
+ public class MinimumChangeCalculator : IChangeCalculator
+ {
+ public IList<(Currency, int)> GetChange(int changeAmount)
+ {
+ List<(Currency Currency, int Quantity)> change = new List<(Currency Currency, int Quantity)>();
+
+ foreach (var currency in Currency.List())
+ {
+ if (changeAmount >= currency.Value)
+ {
+ int quantity = changeAmount / currency.Value;
+ change.Add((Currency: currency, Quantity: quantity));
+ changeAmount -= currency.Value * quantity;
+ }
+ }
+
+ return change;
+ }
+ }
+}
diff --git a/Program.cs b/Program.cs
new file mode 100644
index 00000000..f8450884
--- /dev/null
+++ b/Program.cs
@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.IO;
+using System.Text.RegularExpressions;
+
+namespace SWCashRegister
+{
+ class Program
+ {
+ static void Main(string[] args)
+ {
+ string line;
+
+ if (!System.IO.File.Exists("input.txt"))
+ {
+ Console.WriteLine("Could not find file input.txt.");
+ return;
+ }
+
+ try
+ {
+ using (var input = new StreamReader("input.txt"))
+ using (var output = new StreamWriter("output.txt"))
+ {
+ while ((line = input.ReadLine()) != null)
+ {
+ if (!ValidateLine(line))
+ {
+ Console.WriteLine($"Found invalid value: {line}");
+ continue;
+ }
+
+ var values = line.Split(',');
+ int price = (int)(Convert.ToDecimal(values[0]) * 100);
+ int amountPaid = (int)(Convert.ToDecimal(values[1]) * 100);
+
+ if (amountPaid < price)
+ {
+ Console.WriteLine($"Insufficient funds: {line}");
+ continue;
+ }
+
+ int changeAmount = amountPaid - price;
+
+ IChangeCalculator calculator = ChangeCalculatorFactory.GetChangeCalculator(price);
+ output.WriteLine(PrintChange(calculator.GetChange(changeAmount)));
+ }
+ }
+ }
+ catch (Exception ex)
+ {
+ Console.WriteLine(ex.Message);
+ }
+ finally
+ {
+ Console.WriteLine("Press any key to quit.");
+ Console.ReadKey();
+ }
+ }
+
+ ///
+ /// Returns true if the line contains two decimal values, separated by a comma
+ ///
+ ///
+ /// True if line is correctly formatted
+ public static bool ValidateLine(string line)
+ {
+ var regex = new Regex(@"^\d+\.\d{2}\,\d+\.\d{2}$");
+ return regex.IsMatch(line) ;
+ }
+
+ ///
+ /// Gets a text description of change quantities.
+ ///
+ /// A list mapping a currency to a quantity
+ /// Description of change.
+ public static string PrintChange(IList<(Currency Currency, int Quantity)> change)
+ {
+ List changeText = new List();
+
+ var sortedChange = change
+ .GroupBy(x => x.Currency)
+ .Select(g => new {
+ Currency = g.Key,
+ Quantity = g.Sum(x => x.Quantity)
+ })
+ .OrderByDescending(x => x.Currency.Value);
+
+ foreach (var denomination in sortedChange)
+ {
+ changeText.Add($"{denomination.Quantity} {(denomination.Quantity == 1 ? denomination.Currency.Name : denomination.Currency.Plural)}");
+ }
+
+ return String.Join(",", changeText);
+ }
+ }
+}
diff --git a/Properties/AssemblyInfo.cs b/Properties/AssemblyInfo.cs
new file mode 100644
index 00000000..7043532a
--- /dev/null
+++ b/Properties/AssemblyInfo.cs
@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("SWCashRegister")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("SWCashRegister")]
+[assembly: AssemblyCopyright("Copyright © 2019")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible
+// to COM components. If you need to access a type in this assembly from
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("83c9c135-36e1-4d63-bb89-04367da7da25")]
+
+// Version information for an assembly consists of the following four values:
+//
+// Major Version
+// Minor Version
+// Build Number
+// Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]
diff --git a/RandomChangeCalculator.cs b/RandomChangeCalculator.cs
new file mode 100644
index 00000000..ac012101
--- /dev/null
+++ b/RandomChangeCalculator.cs
@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SWCashRegister
+{
+ public class RandomChangeCalculator : IChangeCalculator
+ {
+ public IList<(Currency, int)> GetChange(int changeAmount)
+ {
+ List<(Currency Currency, int Quantity)> change = new List<(Currency Currency, int Quantity)>();
+ Random random = new Random();
+
+ while (changeAmount > 0)
+ {
+ List availableCurrencies = Currency.List().Where(x => x.Value <= changeAmount).ToList();
+ int index = random.Next(0, availableCurrencies.Count());
+ Currency currency = availableCurrencies[index];
+ change.Add((Currency: currency, Quantity: 1));
+ changeAmount -= currency.Value;
+ }
+
+ return change;
+ }
+ }
+}
diff --git a/SWCashRegister.csproj b/SWCashRegister.csproj
new file mode 100644
index 00000000..c11690a7
--- /dev/null
+++ b/SWCashRegister.csproj
@@ -0,0 +1,62 @@
+
+
+
+
+ Debug
+ AnyCPU
+ {83C9C135-36E1-4D63-BB89-04367DA7DA25}
+ Exe
+ SWCashRegister
+ SWCashRegister
+ v4.7.1
+ 512
+ true
+ true
+
+
+
+ AnyCPU
+ true
+ full
+ false
+ bin\Debug\
+ DEBUG;TRACE
+ prompt
+ 4
+
+
+ AnyCPU
+ pdbonly
+ true
+ bin\Release\
+ TRACE
+ prompt
+ 4
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
\ No newline at end of file
diff --git a/SWCashRegister.sln b/SWCashRegister.sln
new file mode 100644
index 00000000..a8d46f3d
--- /dev/null
+++ b/SWCashRegister.sln
@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 15
+VisualStudioVersion = 15.0.28010.2026
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SWCashRegister", "SWCashRegister.csproj", "{83C9C135-36E1-4D63-BB89-04367DA7DA25}"
+EndProject
+Global
+ GlobalSection(SolutionConfigurationPlatforms) = preSolution
+ Debug|Any CPU = Debug|Any CPU
+ Release|Any CPU = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(ProjectConfigurationPlatforms) = postSolution
+ {83C9C135-36E1-4D63-BB89-04367DA7DA25}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {83C9C135-36E1-4D63-BB89-04367DA7DA25}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {83C9C135-36E1-4D63-BB89-04367DA7DA25}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {83C9C135-36E1-4D63-BB89-04367DA7DA25}.Release|Any CPU.Build.0 = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(SolutionProperties) = preSolution
+ HideSolutionNode = FALSE
+ EndGlobalSection
+ GlobalSection(ExtensibilityGlobals) = postSolution
+ SolutionGuid = {09B5569E-E268-4199-994A-FE759C731E19}
+ EndGlobalSection
+EndGlobal