cs11dotnet7/vscode/Chapter06/PeopleApp/Program.cs

using Packt.Shared;

Person harry = new()
{
  Name = "Harry",
  DateOfBirth = new(year: 2001, month: 3, day: 25)
};

harry.WriteToConsole();

// non-generic lookup collection
System.Collections.Hashtable lookupObject = new();
lookupObject.Add(key: 1, value: "Alpha");
lookupObject.Add(key: 2, value: "Beta");
lookupObject.Add(key: 3, value: "Gamma");
lookupObject.Add(key: harry, value: "Delta");

int key = 2; // look up the value that has 2 as its key

WriteLine(format: "Key {0} has value: {1}",
  arg0: key,
  arg1: lookupObject[key]);

// look up the value that has harry as its key
WriteLine(format: "Key {0} has value: {1}",
  arg0: harry,
  arg1: lookupObject[harry]);

// generic lookup collection
Dictionary<int, string> lookupIntString = new();
lookupIntString.Add(key: 1, value: "Alpha");
lookupIntString.Add(key: 2, value: "Beta");
lookupIntString.Add(key: 3, value: "Gamma");
lookupIntString.Add(key: 4, value: "Delta");

key = 3;

WriteLine(format: "Key {0} has value: {1}",
  arg0: key,
  arg1: lookupIntString[key]);

// Defining and handling delegates

// assign event handler methods to Shout event
harry.Shout += Harry_Shout;
harry.Shout += Harry_Shout2;

// call the Poke method that raises the Shout event
harry.Poke();
harry.Poke();
harry.Poke();
harry.Poke();

// Comparing objects when sorting

Person?[] people =
{
  null,
  new() { Name = "Simon" },
  new() { Name = "Jenny" },
  new() { Name = "Adam" },
  new() { Name = null },
  new() { Name = "Richard" }
};

OutputPeopleNames(people, "Initial list of people:");

Array.Sort(people);

OutputPeopleNames(people, 
  "After sorting using Person's IComparable implementation:");

Array.Sort(people, new PersonComparer());

OutputPeopleNames(people,
  "After sorting using PersonComparer's IComparer implementation:");

// Equality of types

int a = 3;
int b = 3;
WriteLine($"a: {a}, b: {b}");
WriteLine($"a == b: {a == b}");

Person p1 = new() { Name = "Kevin" };
Person p2 = new() { Name = "Kevin" };
WriteLine($"p1: {p1}, p2: {p2}");
WriteLine($"p1 == p2: {p1 == p2}");

Person p3 = p1;
WriteLine($"p3: {p3}");
WriteLine($"p1 == p3: {(p1 == p3)}");

WriteLine($"p1.Name: {p1.Name}, p2.Name: {p2.Name}");
WriteLine($"p1.Name == p2.Name: {p1.Name == p2.Name}");

// Defining struct types

DisplacementVector dv1 = new(3, 5);
DisplacementVector dv2 = new(-2, 7);
DisplacementVector dv3 = dv1 + dv2;
WriteLine($"({dv1.X}, {dv1.Y}) + ({dv2.X}, {dv2.Y}) = ({dv3.X}, {dv3.Y})");

DisplacementVector dv4 = new();
WriteLine($"({dv4.X}, {dv4.Y})");

// Inheriting from classes

Employee john = new()
{
  Name = "John Jones",
  DateOfBirth = new(year: 1990, month: 7, day: 28)
};
john.WriteToConsole();

john.EmployeeCode = "JJ001";
john.HireDate = new(year: 2014, month: 11, day: 23);
WriteLine($"{john.Name} was hired on {john.HireDate:dd/MM/yy}");

WriteLine(john.ToString());

Employee aliceInEmployee = new()
{ Name = "Alice", EmployeeCode = "AA123" };

Person aliceInPerson = aliceInEmployee;
aliceInEmployee.WriteToConsole();
aliceInPerson.WriteToConsole();
WriteLine(aliceInEmployee.ToString());
WriteLine(aliceInPerson.ToString());

if (aliceInPerson is Employee)
{
  WriteLine($"{nameof(aliceInPerson)} IS an Employee");

  Employee explicitAlice = (Employee)aliceInPerson;

  // safely do something with explicitAlice
}

/* alternative syntax
if (aliceInPerson is Employee explicitAlice)  
{
  WriteLine($"{nameof(aliceInPerson)} IS an Employee"); 
  // safely do something with explicitAlice
}
 */

Employee? aliceAsEmployee = aliceInPerson as Employee; // could be null

if (aliceAsEmployee is not null)
{
  WriteLine($"{nameof(aliceInPerson)} AS an Employee");

  // safely do something with aliceAsEmployee
}

try
{
  john.TimeTravel(when: new(1999, 12, 31));
  john.TimeTravel(when: new(1950, 12, 25));
}
catch (PersonException ex)
{
  WriteLine(ex.Message);
}

string email1 = "pamela@test.com";
string email2 = "ian&test.com";

WriteLine("{0} is a valid e-mail address: {1}",
  arg0: email1,
  arg1: StringExtensions.IsValidEmail(email1));

WriteLine("{0} is a valid e-mail address: {1}",
  arg0: email2,
  arg1: StringExtensions.IsValidEmail(email2));

WriteLine("{0} is a valid e-mail address: {1}",
  arg0: email1,
  arg1: email1.IsValidEmail());

WriteLine("{0} is a valid e-mail address: {1}",
  arg0: email2,
  arg1: email2.IsValidEmail());