PI06 i PI06-1. Docker definitions for MSSQL and Postgres. Data seeder/generator for countries and people. Entity Framework example with variants for Postgres and MSSQL

SomeOfCSharpFeatures/CovarianceContravariance/CovarianceContravariance.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="..\Inheritance\Inheritance.csproj" />
+  </ItemGroup>
+
+</Project>

SomeOfCSharpFeatures/CovarianceContravariance/Program.cs

@@ -0,0 +1,49 @@
+using Inheritance;
+
+namespace CovarianceContravariance;
+
+class Program
+{
+  static void Main(string[] args)
+  {
+    List<Car> cars = new List<Car>{
+      new Car("Coupe", 200, 3),
+      new Car("Wagon", 100, 5),
+      new Car("Limousine", 150, 4),
+      new ElectricCar("Electric Hatchback", 148, 5, 40)
+    };
+    PrintVehicles(cars);
+    
+    Comparison<Vehicle> comparisonFunction = (a, b) => -a.HorsePower.CompareTo(b.HorsePower);
+    IComparer<Vehicle> comparer = Comparer<Vehicle>.Create(comparisonFunction);
+
+    PrintBetterCar(cars[2], cars[3], comparer);
+    PrintBetterCar(cars.Skip(2).First(), cars.Last(), comparisonFunction);
+
+    PrintBetterCar(cars[2], cars[3], (a, b) => b.Doors - a.Doors);
+  }
+
+  static void PrintVehicles(IEnumerable<Vehicle> vehicles)
+  {
+    foreach (var vehicle in vehicles)
+    {
+      Console.WriteLine("\t " + vehicle.Model);
+    }
+  }
+
+  static void PrintBetterCar(Car a, Car b, IComparer<Car> comparer)
+  {
+    int result = comparer.Compare(a, b);
+    string betterModel = result <= 0 ? a.Model : b.Model;
+    string worseModel = result <= 0 ? b.Model : a.Model;
+    Console.WriteLine($"\t{betterModel} is better or equal than {worseModel}");
+  }
+
+  static void PrintBetterCar(Car a, Car b, Comparison<Car> comparer)
+  {
+    int result = comparer(a, b);
+    string betterModel = result <= 0 ? a.Model : b.Model;
+    string worseModel = result <= 0 ? b.Model : a.Model;
+    Console.WriteLine($"\t{betterModel} is better or equal than {worseModel}");
+  }
+}

SomeOfCSharpFeatures/Delegates/Delegates.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

SomeOfCSharpFeatures/Delegates/MathTool.cs

@@ -0,0 +1,26 @@
+using System;
+
+namespace Delegates;
+
+public class MathTool
+{
+  public static int Sum(int x, int y)
+  {
+    return x + y;
+  }
+
+  public static int Diff(int x, int y)
+  {
+    return x - y;
+  }
+
+  public static void PrintSquare(int x)
+  {
+    Console.WriteLine("x^2 = " + x * x);
+  }
+
+  public static void PrintSquareRoot(int x)
+  {
+    Console.WriteLine("sqrt(x) = " + Math.Sqrt(x));
+  }
+}

SomeOfCSharpFeatures/Delegates/Program.cs

@@ -0,0 +1,31 @@
+namespace Delegates;
+
+class Program
+{
+  public delegate int MathFunction(int a, int b);
+  public delegate void PrintFunction(int n);
+  static void Main(string[] args)
+  {
+    int x = 16, y = 2;
+    MathFunction mf = MathTool.Sum;
+    Console.WriteLine("mf({0}, {1}) = {2}", x, y, mf(x, y));
+    mf = MathTool.Diff;
+    Console.WriteLine("mf({0}, {1}) = {2}", x, y, mf(x, y));
+    PrintFunction pf = MathTool.PrintSquare;
+    pf += MathTool.PrintSquareRoot;
+    pf(x);
+#pragma warning disable CS8601 // Possible null reference assignment.
+    pf -= MathTool.PrintSquare;
+#pragma warning restore CS8601 // Possible null reference assignment.
+    Console.WriteLine();
+#pragma warning disable CS8602 // Dereference of a possibly null reference.
+    pf(y); //instead of pragma pf?.Invoke(y); can be used  
+#pragma warning restore CS8602 // Dereference of a possibly null reference.
+
+    Func<int, int, int> func = MathTool.Sum;
+    Console.WriteLine("func({0}, {1}) = {2}", x, y, func(x, y));
+    
+    Action<int> action = MathTool.PrintSquare;
+    action(x);
+  }
+}

SomeOfCSharpFeatures/Extensions/Activity.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace Extensions;
+
+[Flags]
+public enum DayPeriod
+{
+  Morning = 1, Evening = 2, Afternoon = 4, Night = 8
+}
+
+public class Activity
+{
+  public required string Person { get; set; }
+  public int Hours { get; set; }
+  public DayPeriod Period { get; set; }
+}

SomeOfCSharpFeatures/Extensions/Extensions.cs

@@ -0,0 +1,18 @@
+using System.Collections.Generic;
+
+namespace Extensions;
+
+public static class Extensions
+{
+  public static V GetOrCreate<K, V>(this Dictionary<K, V> dict, K key) 
+    where V : new()
+    where K: notnull  
+  {
+    if (!dict.TryGetValue(key, out V? value))
+    {
+      value = new V();
+      dict[key] = value;        
+    }
+    return value;            
+  }
+}

SomeOfCSharpFeatures/Extensions/Extensions.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

SomeOfCSharpFeatures/Extensions/Program.cs

@@ -0,0 +1,61 @@
+namespace Extensions;
+
+public enum Days
+{
+  Monday, Tuesday, Wednesday,
+  Thursday, Friday, Saturday, Sunday
+}
+
+class Program
+{    
+  static void Main(string[] args)
+  {
+    var dict = new Dictionary<Days, List<Activity>>();
+    Activity a = new Activity
+    {
+      Person = "John",
+      Hours = 3,
+      Period = DayPeriod.Morning
+    };
+    dict.GetOrCreate(Days.Monday).Add(a);
+
+    a = new Activity
+    {
+      Person = "Mary",
+      Hours = 12,
+      Period = DayPeriod.Evening | DayPeriod.Night
+    };
+    dict.GetOrCreate(Days.Monday).Add(a);
+
+    a = new Activity
+    {
+      Person = "Peter",
+      Hours = 8,
+      Period = DayPeriod.Night
+    };
+    dict.GetOrCreate(Days.Tuesday).Add(a);
+
+    a = new Activity
+    {
+      Person = "Lisa",
+      Hours = 5,
+      Period = DayPeriod.Night | DayPeriod.Morning
+    };
+    dict.GetOrCreate(Days.Monday).Add(a);
+
+    int sum = SumNightActivity(dict);
+    Console.WriteLine(sum);
+
+  }
+
+  private static int SumNightActivity(Dictionary<Days, List<Activity>> dict)
+  {
+    int sum = 0;
+    foreach(var list in dict.Values)
+    {
+      sum += list.Where(a => (a.Period & DayPeriod.Night) == DayPeriod.Night)
+                 .Sum(a => a.Hours);                   
+    }
+    return sum;  
+  }
+}

SomeOfCSharpFeatures/Inheritance/Car.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace Inheritance;
+
+public class Car : Vehicle
+{
+  public int Doors { get; set; }
+  public string Color { get; set; } = "White";
+
+  public Car(string model, double horsePower, int doors) 
+    : base(model, horsePower)
+  {
+    Console.WriteLine($"Creating car {model}");
+    this.Doors = doors;
+  }
+
+  public void BuckleSeatBelt()
+  {
+    Console.WriteLine("Car {0} - seat belt buckled", Model);
+  }
+
+  public override void Start()
+  {
+    Console.WriteLine("Start Car " + Model);
+  }
+
+  public new void Stop()
+  {
+    Console.WriteLine("Stop Car " + Model);
+  }
+}

SomeOfCSharpFeatures/Inheritance/ElectricCar.cs

@@ -0,0 +1,13 @@
+namespace Inheritance;
+
+public class ElectricCar : Car
+{
+  public int BatteryCapacity { get; set; }
+  public int? Range { get; set; }
+
+  public ElectricCar(string model, double horsePower, int doors, int batteryCapacity) :
+    base(model, horsePower, doors)
+  {
+    this.BatteryCapacity = batteryCapacity;
+  }
+}

SomeOfCSharpFeatures/Inheritance/Inheritance.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

SomeOfCSharpFeatures/Inheritance/Motorbike.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace Inheritance;
+
+public class Motorbike : Vehicle
+{
+  public bool HasSidecar { get; set; }
+  public Motorbike(string model, double horsePower, bool sidecar)
+   : base(model, horsePower)
+  {
+    Console.WriteLine($"Creating car {model}");
+    this.HasSidecar = sidecar;
+  }
+  public override void Start()
+  {
+    Console.WriteLine("Start Motorbike " + Model);
+  }
+}

SomeOfCSharpFeatures/Inheritance/Program.cs

@@ -0,0 +1,39 @@
+using Inheritance;
+
+Vehicle v = new Vehicle("BMW Isseta", 9.5);
+v.Start();
+
+Car car = new ElectricCar("Nissan Leaf", 148, 5, 40)
+{
+  Range = 270
+};
+Console.WriteLine("car model = " + car.Model);
+Console.WriteLine("car horse power = " + car.HorsePower);
+Console.WriteLine("car number of doors = " + car.Doors);
+if (car is ElectricCar electric)
+{
+  Console.WriteLine("car battery = " + electric.BatteryCapacity);
+  if (electric.Range.HasValue)
+  {
+    Console.WriteLine("car range = " + electric.Range);
+  }
+}
+
+car.BuckleSeatBelt();
+car.Start();
+car.Stop();
+
+((Vehicle)car).Start();
+((Vehicle)car).Stop();
+
+// objekt tipa Motocikl
+Motorbike moto = new Motorbike("Ural", 41, true);
+Console.WriteLine("motorbike model {0} ", moto.Model);
+Console.WriteLine("motorbike horse power = " + moto.HorsePower);
+Console.WriteLine($"motorbike has sidecar? = {moto.HasSidecar}");
+
+moto.Start();
+moto.Stop();
+
+((Vehicle)moto).Start();
+((Vehicle)moto).Stop();

SomeOfCSharpFeatures/Inheritance/Vehicle.cs

@@ -0,0 +1,26 @@
+using System;
+
+namespace Inheritance;
+
+public class Vehicle
+{
+  public string Model { get; private set; }
+  public double HorsePower { get; set; }
+
+  public Vehicle(string model, double horsePower)
+  {
+    Console.WriteLine("Creating vehicle " + model);
+    this.Model = model;
+    this.HorsePower = horsePower;
+  }
+
+  public void Stop()
+  {
+    Console.WriteLine("Stop vehicle " + Model);
+  }
+
+  public virtual void Start()
+  {
+    Console.WriteLine("Start vehicle " + Model);
+  }
+}

SomeOfCSharpFeatures/PropertiesIndexersRefOut/Program.cs

@@ -0,0 +1,48 @@
+using PropertiesIndexersRefOut;
+
+Triple t1 = new Triple
+{
+  First = 456,
+  Second = 789
+};
+
+Triple t2 = new Triple
+{
+  First = 1000,
+  Second = 2000
+};
+
+Console.WriteLine("t1 + t2 = " + (t1 + t2));
+
+CreateRandomTriple(t1, ref t2, out Triple t3);
+
+Console.WriteLine("t1 = " + t1);
+Console.WriteLine("t2 = " + t2);
+Console.WriteLine("t3 = " + t3);
+
+Console.WriteLine(t1["A", 1]);
+Console.WriteLine(t1["B", 2]);
+Console.WriteLine(t1["B", 3]);
+
+PrintTriples(t1, t2, t3);
+
+void PrintTriples(params Triple[] triples)
+{
+  foreach (var t in triples)
+  {
+    Console.WriteLine(t);
+  }
+}
+
+void CreateRandomTriple(Triple t1, ref Triple t2, out Triple t3)
+{
+  Random r = new Random();
+  t3 = new Triple
+  {
+    First = r.Next(t1.First, t2.Second),
+    Second = r.Next(maxValue: t2.Second, minValue: t1.First)
+  };
+
+  t1 = t3;
+  t2 = t3;
+}

SomeOfCSharpFeatures/PropertiesIndexersRefOut/PropertiesIndexersRefOut.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

SomeOfCSharpFeatures/PropertiesIndexersRefOut/Triple.cs

@@ -0,0 +1,73 @@
+namespace PropertiesIndexersRefOut;
+
+public class Triple
+{
+  private int first;
+  public int First
+  {
+    get
+    {
+      return first;
+    }
+    set
+    {
+      first = value;
+    }
+  }
+
+  public int Second { get; set; }
+
+  public int Third => First + Second;
+  public override string ToString()
+  {
+    return $"({First}, {Second}, {Third})";
+  }
+
+  #region Indexer
+  public int this[string s, int position]  
+  {      
+    get
+    {        
+      int num;
+      switch (s)
+      {
+        case "A":
+          num = this.First;
+          break;
+        case "B":
+          num = this.Second;
+          break;
+        case "C":
+          num = this.Third;
+          break;
+        default:
+          throw new ArgumentException("Invalid position in triple (should be A, B, or C)");
+      }
+      int digit = 0;
+      while(num > 0 && position > 0)
+      {
+        digit = num % 10;
+        num /= 10;
+        position--;
+      }
+      return digit;
+    }
+  }
+  #endregion
+
+
+  #region Operator overloading
+  public static Triple operator +(Triple x, Triple y)
+  {    
+    return new Triple
+    {
+      First = x.First + y.First,
+      Second = x.Second + y.Second
+    };
+  }
+  #endregion
+
+
+
+
+}

SomeOfCSharpFeatures/SomeOfCSharpFeatures.sln

@@ -0,0 +1,55 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.5.33424.131
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Delegates", "Delegates\Delegates.csproj", "{EABA8FC4-42FB-4DAD-96E9-47A5B1057CFB}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Extensions", "Extensions\Extensions.csproj", "{47B09D5D-50E4-4827-B954-A40B96052B83}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CovarianceContravariance", "CovarianceContravariance\CovarianceContravariance.csproj", "{007533F4-FE60-4E0C-AF11-004BF8A2C8F8}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Inheritance", "Inheritance\Inheritance.csproj", "{BEB733F2-BBB4-4170-B530-EFF7C5797559}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "PropertiesIndexersRefOut", "PropertiesIndexersRefOut\PropertiesIndexersRefOut.csproj", "{C6F8925F-2947-4A78-8E1A-543D13B7ED6B}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ValueTuplesDeconstruction", "ValueTuplesDeconstruction\ValueTuplesDeconstruction.csproj", "{2518859E-D8D5-418A-A92B-411277F86479}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{EABA8FC4-42FB-4DAD-96E9-47A5B1057CFB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{EABA8FC4-42FB-4DAD-96E9-47A5B1057CFB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{EABA8FC4-42FB-4DAD-96E9-47A5B1057CFB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{EABA8FC4-42FB-4DAD-96E9-47A5B1057CFB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{47B09D5D-50E4-4827-B954-A40B96052B83}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{47B09D5D-50E4-4827-B954-A40B96052B83}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{47B09D5D-50E4-4827-B954-A40B96052B83}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{47B09D5D-50E4-4827-B954-A40B96052B83}.Release|Any CPU.Build.0 = Release|Any CPU
+		{007533F4-FE60-4E0C-AF11-004BF8A2C8F8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{007533F4-FE60-4E0C-AF11-004BF8A2C8F8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{007533F4-FE60-4E0C-AF11-004BF8A2C8F8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{007533F4-FE60-4E0C-AF11-004BF8A2C8F8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BEB733F2-BBB4-4170-B530-EFF7C5797559}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BEB733F2-BBB4-4170-B530-EFF7C5797559}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BEB733F2-BBB4-4170-B530-EFF7C5797559}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BEB733F2-BBB4-4170-B530-EFF7C5797559}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C6F8925F-2947-4A78-8E1A-543D13B7ED6B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C6F8925F-2947-4A78-8E1A-543D13B7ED6B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C6F8925F-2947-4A78-8E1A-543D13B7ED6B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C6F8925F-2947-4A78-8E1A-543D13B7ED6B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{2518859E-D8D5-418A-A92B-411277F86479}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2518859E-D8D5-418A-A92B-411277F86479}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2518859E-D8D5-418A-A92B-411277F86479}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2518859E-D8D5-418A-A92B-411277F86479}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {88C158C1-838B-42EB-A159-F5F83BF2DDEA}
+	EndGlobalSection
+EndGlobal

SomeOfCSharpFeatures/ValueTuplesDeconstruction/Program.cs

@@ -0,0 +1,22 @@
+//ValueTuples https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/functional/deconstruct
+
+(int a, int b, int _) t1 = CreateRandomTriple();
+Console.WriteLine(t1);
+Console.WriteLine(t1.b);
+
+var (_, b, _) = CreateRandomTriple();
+Console.WriteLine(b);
+
+
+var t2 = CreateRandomTriple();
+Console.WriteLine(t2);
+Console.WriteLine(t2.Item2);
+
+(int, int, int) CreateRandomTriple()
+{
+  Random r = new Random();
+  var triple = (r.Next(100), r.Next(100), r.Next(100));
+  Console.WriteLine($"Created {triple}");
+  return triple;
+}
+ 

SomeOfCSharpFeatures/ValueTuplesDeconstruction/ValueTuplesDeconstruction.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>