Initial commit

vscode/Chapter06/PeopleApp/Program.cs

@@ -0,0 +1,184 @@
+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; // lookup the value that has 2 as its key
+
+WriteLine(format: "Key {0} has value: {1}",
+  arg0: key,
+  arg1: lookupObject[key]);
+
+// lookup 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());