Added challenge functions

.gitignore

@@ -454,4 +454,3 @@ $RECYCLE.BIN/
 !.vscode/extensions.json
 /Calculator.TomDonegan/TextFile1.txt
 /Calculator.TomDonegan/Calculator.TomDonegan/Notes.txt
-/Calculator

Calculator/Calculator.slnx

@@ -0,0 +1,4 @@
+<Solution>
+  <Project Path="CalculatorApp/CalculatorApp.csproj" />
+  <Project Path="CalculatorLibrary/CalculatorLibrary.csproj" Id="dd72f64f-91a3-4584-a368-a9469274340c" />
+</Solution>

Calculator/CalculatorApp/CalculatorApp.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\CalculatorLibrary\CalculatorLibrary.csproj" />
+  </ItemGroup>
+
+</Project>

Calculator/CalculatorApp/Program.cs

@@ -0,0 +1,135 @@
+// Program.cs
+using System.Text.RegularExpressions;
+using CalculatorLibrary;
+
+namespace CalculatorProgram;
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        bool endApp = false;
+        List<Calculation> calcHistory = new();
+
+        // Display title as the C# console calculator app.
+        Console.WriteLine("Console Calculator in C#\r");
+        Console.WriteLine("------------------------\n");
+
+        Calculator calculator = new Calculator();
+        while (!endApp)
+        {
+            // Declare variables and set to empty.
+            // Use Nullable types (with ?) to match type of System.Console.ReadLine
+            string? numInput1 = "";
+            string? numInput2 = "";
+            double result = 0;
+
+            // Ask the user to type the first number.
+            Console.Write("Type a number, and then press Enter (or press [ x ] to use last calculation result): ");
+            numInput1 = Console.ReadLine();
+
+            if (numInput1 == "x" && calcHistory.Count >= 1)
+            {
+                numInput1 = calcHistory[calcHistory.Count - 1].Result.ToString();
+                Console.WriteLine($"Your first number is {numInput1}");
+            }
+            else if (numInput1 == "x" && calcHistory.Count < 1)
+            {
+                Console.WriteLine("No history exists...");
+            }
+
+            double cleanNum1 = 0;
+            while (!double.TryParse(numInput1, out cleanNum1))
+            {
+                Console.Write("This is not valid input. Please enter an integer value: ");
+                numInput1 = Console.ReadLine();
+            }
+
+            // Ask the user to type the second number.
+            Console.Write("Type another number, and then press Enter (or press [ x ] to use last calculation result): ");
+            numInput2 = Console.ReadLine();
+
+            if (numInput2 == "x" && calcHistory.Count >= 1)
+            {
+                numInput2 = calcHistory[calcHistory.Count - 1].Result.ToString();
+                Console.WriteLine($"Your first number is {numInput1}");
+            }
+            else if (numInput2 == "x" && calcHistory.Count < 1)
+            {
+                Console.WriteLine("No history exists...");
+            }
+
+            double cleanNum2 = 0;
+            while (!double.TryParse(numInput2, out cleanNum2))
+            {
+                Console.Write("This is not valid input. Please enter an integer value: ");
+                numInput2 = Console.ReadLine();
+            }
+
+            // Ask the user to choose an operator.
+            Console.WriteLine("Choose an operator from the following list:");
+            Console.WriteLine("\ta - Add");
+            Console.WriteLine("\ts - Subtract");
+            Console.WriteLine("\tm - Multiply");
+            Console.WriteLine("\td - Divide");
+            Console.WriteLine("\tp - Power (first number to power of second number)");
+
+            Console.Write("Your option? ");
+
+            string? op = Console.ReadLine();
+
+            // Validate input is not null, and matches the pattern
+            if (op == null || !Regex.IsMatch(op, "[a|s|m|d|p]"))
+            {
+                Console.WriteLine("Error: Unrecognized input.");
+            }
+            else
+            {
+                try
+                {
+                    result = calculator.DoOperation(cleanNum1, cleanNum2, op);
+                    if (double.IsNaN(result))
+                    {
+                        Console.WriteLine("This operation will result in a mathematical error.\n");
+                    }
+                    else
+                    {
+                        calcHistory.Add(new Calculation()
+                        {
+                            FirstNum = cleanNum1,
+                            SecondNum = cleanNum2,
+                            Result = result
+                        });
+                        Console.WriteLine("Your result: {0:0.##}\n", result);
+                        Console.WriteLine($"You have used the calculator {calcHistory.Count} times");
+                        if (calcHistory.Count > 0)
+                        {
+                            Console.WriteLine("Would you like to clear the history [Y/N]?");
+                            string userInput = Console.ReadLine().ToLower();
+                            if (userInput == "y")
+                            {
+                                calcHistory.Clear();
+                                Console.WriteLine("History cleared!");
+                            }
+                        }
+                    }
+                }
+                catch (Exception e)
+                {
+                    Console.WriteLine("Oh no! An exception occurred trying to do the math.\n - Details: " + e.Message);
+                }
+
+
+            }
+            Console.WriteLine("------------------------\n");
+
+            // Wait for the user to respond before closing.
+            Console.Write("Press 'x' and Enter to close the app, or press any other key and Enter to continue: ");
+            if (Console.ReadLine() == "x") endApp = true;
+
+            Console.WriteLine("\n"); // Friendly linespacing.
+        }
+        calculator.Finish();
+        return;
+    }
+}

Calculator/CalculatorLibrary/CalculatorLibrary.cs

@@ -0,0 +1,81 @@
+// CalculatorLibrary.cs
+using Newtonsoft.Json;
+
+namespace CalculatorLibrary;
+
+public class Calculator
+{
+    JsonWriter writer;
+
+    public Calculator()
+    {
+        StreamWriter logFile = File.CreateText("calculatorlog.json");
+        logFile.AutoFlush = true;
+        writer = new JsonTextWriter(logFile);
+        writer.Formatting = Formatting.Indented;
+        writer.WriteStartObject();
+        writer.WritePropertyName("Operations");
+        writer.WriteStartArray();
+    }
+
+    public double DoOperation(double num1, double num2, string op)
+    {
+        double result = double.NaN; // Default value is "not-a-number" if an operation, such as division, could result in an error.
+        writer.WriteStartObject();
+        writer.WritePropertyName("Operand1");
+        writer.WriteValue(num1);
+        writer.WritePropertyName("Operand2");
+        writer.WriteValue(num2);
+        writer.WritePropertyName("Operation");
+        // Use a switch statement to do the math.
+        switch (op)
+        {
+            case "a":
+                result = num1 + num2;
+                writer.WriteValue("Add");
+                break;
+            case "s":
+                result = num1 - num2;
+                writer.WriteValue("Subtract");
+                break;
+            case "m":
+                result = num1 * num2;
+                writer.WriteValue("Multiply");
+                break;
+            case "d":
+                // Ask the user to enter a non-zero divisor.
+                if (num2 != 0)
+                {
+                    result = num1 / num2;
+                }
+                writer.WriteValue("Divide");
+                break;
+            case "p":
+                result = Math.Pow(num1, num2);
+                writer.WriteValue("Power");
+                break;
+            // Return text for an incorrect option entry.
+            default:
+                break;
+        }
+        writer.WritePropertyName("Result");
+        writer.WriteValue(result);
+        writer.WriteEndObject();
+
+        return result;
+    }
+
+    public void Finish()
+    {
+        writer.WriteEndArray();
+        writer.WriteEndObject();
+        writer.Close();
+    }
+}
+
+public class Calculation
+{
+    public double FirstNum { get; set; }
+    public double SecondNum { get; set; }
+    public double Result { get; set; }
+}

Calculator/CalculatorLibrary/CalculatorLibrary.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.4" />
+  </ItemGroup>
+
+</Project>