Initial commit

vs4win/Chapter06/PacktLibrary/DisplacementVector.cs

@@ -0,0 +1,22 @@
+namespace Packt.Shared;
+
+public struct DisplacementVector
+{
+  public int X { get; set; }
+  public int Y { get; set; }
+
+  public DisplacementVector(int initialX, int initialY)
+  {
+    X = initialX;
+    Y = initialY;
+  }
+
+  public static DisplacementVector operator +(
+    DisplacementVector vector1,
+    DisplacementVector vector2)
+  {
+    return new(
+      vector1.X + vector2.X,
+      vector1.Y + vector2.Y);
+  }
+}

vs4win/Chapter06/PacktLibrary/DvdPlayer.cs

@@ -0,0 +1,14 @@
+namespace Packt.Shared;
+
+public class DvdPlayer : IPlayable
+{
+  public void Pause()
+  {
+    WriteLine("DVD player is pausing.");
+  }
+
+  public void Play()
+  {
+    WriteLine("DVD player is playing.");
+  }
+}

vs4win/Chapter06/PacktLibrary/Employee.cs

@@ -0,0 +1,22 @@
+namespace Packt.Shared;
+
+public class Employee : Person
+{
+  public string? EmployeeCode { get; set; }
+  public DateTime HireDate { get; set; }
+
+  public new void WriteToConsole()
+  {
+    WriteLine(format:
+      "{0} was born on {1:dd/MM/yy} and hired on {2:dd/MM/yy}",
+      arg0: Name,
+      arg1: DateOfBirth,
+      arg2: HireDate);
+  }
+
+  public override string ToString()
+  {
+    return $"{Name}'s code is {EmployeeCode}";
+  }
+
+}

vs4win/Chapter06/PacktLibrary/IPlayable.cs

@@ -0,0 +1,11 @@
+namespace Packt.Shared;
+
+public interface IPlayable
+{
+  void Play();
+  void Pause();
+  void Stop() // default interface implementation
+  {
+    WriteLine("Default implementation of Stop.");
+  }
+}

vs4win/Chapter06/PacktLibrary/PacktLibrary.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+	<ItemGroup>
+		<Using Include="System.Console" Static="true" />
+	</ItemGroup>
+
+</Project>

vs4win/Chapter06/PacktLibrary/Person.cs

@@ -0,0 +1,98 @@
+namespace Packt.Shared;
+
+public class Person : object, IComparable<Person?>
+{
+  // properties
+  public string? Name { get; set; }
+  public DateTime DateOfBirth { get; set; }
+
+  // methods
+  public void WriteToConsole()
+  {
+    WriteLine($"{Name} was born on a {DateOfBirth:dddd}.");
+  }
+
+  // delegate field
+  public event EventHandler? Shout;
+
+  // data field
+  public int AngerLevel;
+
+  // method
+  public void Poke()
+  {
+    AngerLevel++;
+    if (AngerLevel >= 3)
+    {
+      /*
+      // if something is listening...
+      if (Shout != null)
+      {
+        // ...then call the delegate
+        Shout(this, EventArgs.Empty);
+      }
+      */
+
+      // simplified syntax available in C# 6 or later
+      Shout?.Invoke(this, EventArgs.Empty);
+    }
+  }
+
+  public int CompareTo(Person? other)
+  {
+    int position;
+    if ((this is not null) && (other is not null))
+    {
+      if ((Name is not null) && (other.Name is not null))
+      {
+        // if both Name values are not null,
+        // use the string implementation of CompareTo
+        position = Name.CompareTo(other.Name);
+      }
+      else if ((Name is not null) && (other.Name is null))
+      {
+        position = -1; // else this Person precedes other Person
+      }
+      else if ((Name is null) && (other.Name is not null))
+      {
+        position = 1; // else this Person follows other Person
+      }
+      else
+      {
+        position = 0; // this Person and other Person are at same position
+      }
+    }
+    else if ((this is not null) && (other is null))
+    {
+      position = -1; // this Person precedes other Person
+    }
+    else if ((this is null) && (other is not null))
+    {
+      position = 1; // this Person follows other Person
+    }
+    else
+    {
+      position = 0; // this Person and other Person are at same position
+    }
+    return position;
+  }
+
+  // overridden methods
+  public override string ToString()
+  {
+    return $"{Name} is a {base.ToString()}";
+  }
+
+  public void TimeTravel(DateTime when)
+  {
+    if (when <= DateOfBirth)
+    {
+      throw new PersonException("If you travel back in time to a date earlier than your own birth, then the universe will explode!");
+    }
+    else
+    {
+      WriteLine($"Welcome to {when:yyyy}!");
+    }
+  }
+
+}

vs4win/Chapter06/PacktLibrary/PersonComparer.cs

@@ -0,0 +1,56 @@
+namespace Packt.Shared;
+
+public class PersonComparer : IComparer<Person?>
+{
+  public int Compare(Person? x, Person? y)
+  {
+    int position;
+    if ((x is not null) && (y is not null))
+    {
+      if ((x.Name is not null) && (y.Name is not null))
+      {
+        // if both Name values are not null...
+
+        // ...compare the Name lengths...
+        int result = x.Name.Length.CompareTo(y.Name.Length);
+
+        /// ...if they are equal... 
+        if (result == 0)
+        {
+          // ...then compare by the Names...
+          return x.Name.CompareTo(y.Name);
+        }
+        else
+        {
+          // ...otherwise compare by the lengths.
+          position = result;
+        }
+      }
+      else if ((x.Name is not null) && (y.Name is null))
+      {
+        position = -1; // else x Person precedes y Person
+      }
+      else if ((x.Name is null) && (y.Name is not null))
+      {
+        position = 1; // else x Person follows y Person
+      }
+      else
+      {
+        position = 0; // x Person and y Person are at same position
+      }
+    }
+    else if ((x is not null) && (y is null))
+    {
+      position = -1; // x Person precedes y Person
+    }
+    else if ((x is null) && (y is not null))
+    {
+      position = 1; // x Person follows y Person
+    }
+    else
+    {
+      position = 0; // x Person and y Person are at same position
+    }
+    return position;
+  }
+}

vs4win/Chapter06/PacktLibrary/PersonException.cs

@@ -0,0 +1,11 @@
+namespace Packt.Shared;
+
+public class PersonException : Exception
+{
+  public PersonException() : base() { }
+
+  public PersonException(string message) : base(message) { }
+
+  public PersonException(string message, Exception innerException)
+    : base(message, innerException) { }
+}

vs4win/Chapter06/PacktLibrary/StringExtensions.cs

@@ -0,0 +1,15 @@
+using System.Text.RegularExpressions; // to get Regex
+
+namespace Packt.Shared;
+
+public static class StringExtensions
+{
+  public static bool IsValidEmail(this string input)
+  {
+    // use a simple regular expression to check
+    // that the input string is a valid email
+
+    return Regex.IsMatch(input,
+      @"[a-zA-Z0-9\.-_]+@[a-zA-Z0-9\.-_]+");
+  }
+}