Initial commit

.gitignore

+## Ignore Visual Studio temporary files, build results, and
+## files generated by popular Visual Studio add-ons.
+##
+## Get latest from `dotnet new gitignore`
+
+# dotenv files
+.env
+
+# User-specific files
+*.rsuser
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+
+# User-specific files (MonoDevelop/Xamarin Studio)
+*.userprefs
+
+# Mono auto generated files
+mono_crash.*
+
+# Build results
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+[Ww][Ii][Nn]32/
+[Aa][Rr][Mm]/
+[Aa][Rr][Mm]64/
+bld/
+[Bb]in/
+[Oo]bj/
+[Ll]og/
+[Ll]ogs/
+
+# Visual Studio 2015/2017 cache/options directory
+.vs/
+# Uncomment if you have tasks that create the project's static files in wwwroot
+#wwwroot/
+
+# Visual Studio 2017 auto generated files
+Generated\ Files/
+
+# MSTest test Results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+
+# NUnit
+*.VisualState.xml
+TestResult.xml
+nunit-*.xml
+
+# Build Results of an ATL Project
+[Dd]ebugPS/
+[Rr]eleasePS/
+dlldata.c
+
+# Benchmark Results
+BenchmarkDotNet.Artifacts/
+
+# .NET
+project.lock.json
+project.fragment.lock.json
+artifacts/
+
+# Tye
+.tye/
+
+# ASP.NET Scaffolding
+ScaffoldingReadMe.txt
+
+# StyleCop
+StyleCopReport.xml
+
+# Files built by Visual Studio
+*_i.c
+*_p.c
+*_h.h
+*.ilk
+*.meta
+*.obj
+*.iobj
+*.pch
+*.pdb
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+*.pgd
+*.rsp
+*.sbr
+*.tlb
+*.tli
+*.tlh
+*.tmp
+*.tmp_proj
+*_wpftmp.csproj
+*.log
+*.tlog
+*.vspscc
+*.vssscc
+.builds
+*.pidb
+*.svclog
+*.scc
+
+# Chutzpah Test files
+_Chutzpah*
+
+# Visual C++ cache files
+ipch/
+*.aps
+*.ncb
+*.opendb
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+*.cachefile
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+# Visual Studio profiler
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+# Visual Studio Trace Files
+*.e2e
+
+# TFS 2012 Local Workspace
+$tf/
+
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+*.gpState
+
+# ReSharper is a .NET coding add-in
+_ReSharper*/
+*.[Rr]e[Ss]harper
+*.DotSettings.user
+
+# TeamCity is a build add-in
+_TeamCity*
+
+# DotCover is a Code Coverage Tool
+*.dotCover
+
+# AxoCover is a Code Coverage Tool
+.axoCover/*
+!.axoCover/settings.json
+
+# Coverlet is a free, cross platform Code Coverage Tool
+coverage*.json
+coverage*.xml
+coverage*.info
+
+# Visual Studio code coverage results
+*.coverage
+*.coveragexml
+
+# NCrunch
+_NCrunch_*
+.*crunch*.local.xml
+nCrunchTemp_*
+
+# MightyMoose
+*.mm.*
+AutoTest.Net/
+
+# Web workbench (sass)
+.sass-cache/
+
+# Installshield output folder
+[Ee]xpress/
+
+# DocProject is a documentation generator add-in
+DocProject/buildhelp/
+DocProject/Help/*.HxT
+DocProject/Help/*.HxC
+DocProject/Help/*.hhc
+DocProject/Help/*.hhk
+DocProject/Help/*.hhp
+DocProject/Help/Html2
+DocProject/Help/html
+
+# Click-Once directory
+publish/
+
+# Publish Web Output
+*.[Pp]ublish.xml
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+# Note: Comment the next line if you want to checkin your web deploy settings,
+# but database connection strings (with potential passwords) will be unencrypted
+*.pubxml
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+
+# Microsoft Azure Web App publish settings. Comment the next line if you want to
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+# in these scripts will be unencrypted
+PublishScripts/
+
+# NuGet Packages
+*.nupkg
+# NuGet Symbol Packages
+*.snupkg
+# The packages folder can be ignored because of Package Restore
+**/[Pp]ackages/*
+# except build/, which is used as an MSBuild target.
+!**/[Pp]ackages/build/
+# Uncomment if necessary however generally it will be regenerated when needed
+#!**/[Pp]ackages/repositories.config
+# NuGet v3's project.json files produces more ignorable files
+*.nuget.props
+*.nuget.targets
+
+# Microsoft Azure Build Output
+csx/
+*.build.csdef
+
+# Microsoft Azure Emulator
+ecf/
+rcf/
+
+# Windows Store app package directories and files
+AppPackages/
+BundleArtifacts/
+Package.StoreAssociation.xml
+_pkginfo.txt
+*.appx
+*.appxbundle
+*.appxupload
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+*.[Cc]ache
+# but keep track of directories ending in .cache
+!?*.[Cc]ache/
+
+# Others
+ClientBin/
+~$*
+*~
+*.dbmdl
+*.dbproj.schemaview
+*.jfm
+*.pfx
+*.publishsettings
+orleans.codegen.cs
+
+# Including strong name files can present a security risk
+# (https://github.com/github/gitignore/pull/2483#issue-259490424)
+#*.snk
+
+# Since there are multiple workflows, uncomment next line to ignore bower_components
+# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
+#bower_components/
+
+# RIA/Silverlight projects
+Generated_Code/
+
+# Backup & report files from converting an old project file
+# to a newer Visual Studio version. Backup files are not needed,
+# because we have git ;-)
+_UpgradeReport_Files/
+Backup*/
+UpgradeLog*.XML
+UpgradeLog*.htm
+ServiceFabricBackup/
+*.rptproj.bak
+
+# SQL Server files
+*.mdf
+*.ldf
+*.ndf
+
+# Business Intelligence projects
+*.rdl.data
+*.bim.layout
+*.bim_*.settings
+*.rptproj.rsuser
+*- [Bb]ackup.rdl
+*- [Bb]ackup ([0-9]).rdl
+*- [Bb]ackup ([0-9][0-9]).rdl
+
+# Microsoft Fakes
+FakesAssemblies/
+
+# GhostDoc plugin setting file
+*.GhostDoc.xml
+
+# Node.js Tools for Visual Studio
+.ntvs_analysis.dat
+node_modules/
+
+# Visual Studio 6 build log
+*.plg
+
+# Visual Studio 6 workspace options file
+*.opt
+
+# Visual Studio 6 auto-generated workspace file (contains which files were open etc.)
+*.vbw
+
+# Visual Studio 6 auto-generated project file (contains which files were open etc.)
+*.vbp
+
+# Visual Studio 6 workspace and project file (working project files containing files to include in project)
+*.dsw
+*.dsp
+
+# Visual Studio 6 technical files
+*.ncb
+*.aps
+
+# Visual Studio LightSwitch build output
+**/*.HTMLClient/GeneratedArtifacts
+**/*.DesktopClient/GeneratedArtifacts
+**/*.DesktopClient/ModelManifest.xml
+**/*.Server/GeneratedArtifacts
+**/*.Server/ModelManifest.xml
+_Pvt_Extensions
+
+# Paket dependency manager
+.paket/paket.exe
+paket-files/
+
+# FAKE - F# Make
+.fake/
+
+# CodeRush personal settings
+.cr/personal
+
+# Python Tools for Visual Studio (PTVS)
+__pycache__/
+*.pyc
+
+# Cake - Uncomment if you are using it
+# tools/**
+# !tools/packages.config
+
+# Tabs Studio
+*.tss
+
+# Telerik's JustMock configuration file
+*.jmconfig
+
+# BizTalk build output
+*.btp.cs
+*.btm.cs
+*.odx.cs
+*.xsd.cs
+
+# OpenCover UI analysis results
+OpenCover/
+
+# Azure Stream Analytics local run output
+ASALocalRun/
+
+# MSBuild Binary and Structured Log
+*.binlog
+
+# NVidia Nsight GPU debugger configuration file
+*.nvuser
+
+# MFractors (Xamarin productivity tool) working folder
+.mfractor/
+
+# Local History for Visual Studio
+.localhistory/
+
+# Visual Studio History (VSHistory) files
+.vshistory/
+
+# BeatPulse healthcheck temp database
+healthchecksdb
+
+# Backup folder for Package Reference Convert tool in Visual Studio 2017
+MigrationBackup/
+
+# Ionide (cross platform F# VS Code tools) working folder
+.ionide/
+
+# Fody - auto-generated XML schema
+FodyWeavers.xsd
+
+# VS Code files for those working on multiple tools
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+*.code-workspace
+
+# Local History for Visual Studio Code
+.history/
+
+# Windows Installer files from build outputs
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# JetBrains Rider
+*.sln.iml
+.idea
+
+##
+## Visual studio for Mac
+##
+
+
+# globs
+Makefile.in
+*.userprefs
+*.usertasks
+config.make
+config.status
+aclocal.m4
+install-sh
+autom4te.cache/
+*.tar.gz
+tarballs/
+test-results/
+
+# Mac bundle stuff
+*.dmg
+*.app
+
+# content below from: https://github.com/github/gitignore/blob/master/Global/macOS.gitignore
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+# content below from: https://github.com/github/gitignore/blob/master/Global/Windows.gitignore
+# Windows thumbnail cache files
+Thumbs.db
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+# Vim temporary swap files
+*.swp

Abstraction/Abstraction.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

Abstraction/CourseRegistration.cs

+using Abstraction.Notifications;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Abstraction
+{
+
+    public class CourseRegistration
+    {
+        private readonly INotificationService _notificationService;
+
+        // Missing class context in the original slide is supplied here.
+        public CourseRegistration(INotificationService notificationService)
+        {
+            _notificationService = notificationService;
+        }
+
+        public void RegisterStudent()
+        {
+            Console.WriteLine("Student enrolled.");
+            _notificationService.SendNotification("student@gmail.com", "Welcome!");
+        }
+    }
+}

Abstraction/Notifications/EmailService.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Abstraction.Notifications
+{
+    public class EmailService : INotificationService
+    {
+        public void SendNotification(string email, string message)
+        {
+            // Simulated notification; no real SMTP connection.
+            Console.WriteLine($"Email sent to {email}: {message}");
+        }
+    }
+}

Abstraction/Notifications/INotificationService.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Abstraction.Notifications
+{
+    public interface INotificationService
+    {
+        void SendNotification(string email, string message);
+    }
+}

Abstraction/Notifications/SmsService.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Abstraction.Notifications
+{
+    public class SmsService : INotificationService
+    {
+        public void SendNotification(string email, string message)
+        {
+            Console.WriteLine($"SMS simulation for {email}: {message}");
+        }
+    }
+}

Abstraction/Program.cs

+using Abstraction;
+using Abstraction.Notifications;
+using System;
+
+Console.WriteLine("ABSTRACTION — Course registration");
+INotificationService notificationService = new EmailService();
+CourseRegistration registration = new CourseRegistration(notificationService);
+registration.RegisterStudent();
+
+// The service can later be switched without changing the registration class.
+registration = new CourseRegistration(new SmsService());
+registration.RegisterStudent();
+
+

Enacpsulation/Enacpsulation.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

Enacpsulation/Program.cs

+using Enacpsulation;
+using System;
+
+Console.WriteLine("ENCAPSULATION — Student portal");
+
+// Before: any caller can assign an invalid value.
+StudentExamV1 studentV1 = new StudentExamV1();
+studentV1.Grade = 50;
+
+studentV1.Grade = 140;
+
+Console.WriteLine($"Initial Grade: {studentV1.Grade}");
+studentV1.Grade = 999;
+Console.WriteLine($"Invalid Grade is accepted: {studentV1.Grade}");
+
+// After: validated access through public methods.
+StudentExam student = new StudentExam();
+student.SetScore(90);
+Console.WriteLine($"Validated score: {student.GetScore()}");
+
+
+    student.SetScore(999);
+
+

Enacpsulation/StudentExam.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Enacpsulation
+{
+    public class StudentExam
+    {
+        private int _score;
+
+        public void SetScore(int score)
+        {
+            if (score < 0 || score > 100)
+            {
+                throw new ArgumentException("Score must be between 0 and 100.");
+            }
+            _score = score;
+        }
+
+        public int GetScore()
+        {
+            return _score;
+        }
+    }
+
+}

Enacpsulation/StudentExamV1.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Enacpsulation
+{
+    public class StudentExamV1
+    {
+        public int Grade;
+    }
+}

OOPLab.sln

+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.11.35312.102
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Enacpsulation", "Enacpsulation\Enacpsulation.csproj", "{D2C9845D-A104-4613-B12C-52526528D86F}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Abstraction", "Abstraction\Abstraction.csproj", "{AF91227E-B451-40F5-B8AF-EE33D5014AE9}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Polymorphism", "Polymorphism\Polymorphism.csproj", "{5C1EEBFB-C166-4733-A2DF-930C978D3481}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{D2C9845D-A104-4613-B12C-52526528D86F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D2C9845D-A104-4613-B12C-52526528D86F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D2C9845D-A104-4613-B12C-52526528D86F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D2C9845D-A104-4613-B12C-52526528D86F}.Release|Any CPU.Build.0 = Release|Any CPU
+		{AF91227E-B451-40F5-B8AF-EE33D5014AE9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{AF91227E-B451-40F5-B8AF-EE33D5014AE9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{AF91227E-B451-40F5-B8AF-EE33D5014AE9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{AF91227E-B451-40F5-B8AF-EE33D5014AE9}.Release|Any CPU.Build.0 = Release|Any CPU
+		{5C1EEBFB-C166-4733-A2DF-930C978D3481}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5C1EEBFB-C166-4733-A2DF-930C978D3481}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5C1EEBFB-C166-4733-A2DF-930C978D3481}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5C1EEBFB-C166-4733-A2DF-930C978D3481}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {9859C0F4-E012-414C-8A10-BF2D81C388B3}
+	EndGlobalSection
+EndGlobal

OOPLab/Exams/StudentExam.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace OOPLab.Exams
+{
+    public class StudentExam
+    {
+        private int _score;
+
+        public void SetScore(int score)
+        {
+            if (score < 0 || score > 100)
+            {
+                throw new ArgumentException("Score must be between 0 and 100.");
+            }
+            _score = score;
+        }
+
+        public int GetScore()
+        {
+            return _score;
+        }
+    }
+
+}

OOPLab/Exams/StudentExamV1.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace OOPLab.Exams
+{
+    public class StudentExamV1
+    {
+        public int Grade;
+    }
+}

OOPLab/OOPLab.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

OOPLab/Program.cs

+using OOPLab;
+using OOPLab.Exams;
+using System;
+
+Console.WriteLine("ENCAPSULATION — Student portal");
+
+// Before: any caller can assign an invalid value.
+StudentExamV1 studentV1 = new StudentExamV1();
+studentV1.Grade = 50;
+Console.WriteLine($"Initial Grade: {studentV1.Grade}");
+studentV1.Grade = 999;
+Console.WriteLine($"Invalid Grade is accepted: {studentV1.Grade}");
+
+// After: validated access through public methods.
+StudentExam student = new StudentExam();
+student.SetScore(90);
+Console.WriteLine($"Validated score: {student.GetScore()}");
+try
+{
+    student.SetScore(999);
+}
+catch (ArgumentException ex)
+{
+    Console.WriteLine($"Invalid score rejected: {ex.Message}");
+}
+
+
+

Polymorphism/CourseManager.cs

+using Polymorphism.Lessones;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Polymorphism
+{
+    public class CourseManager
+    {
+        public void PlayCourse(List<Lesson> playlist)
+        {
+            foreach (var lesson in playlist)
+            {
+                lesson.Render();
+            }
+        }
+    }
+}

Polymorphism/Lessones/Lesson.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Polymorphism.Lessones
+{
+    public abstract class Lesson
+    {
+        public string Title { get; set; } = string.Empty;
+        public int DurationMinutes { get; set; }
+        public abstract void Render();
+    }
+}

Polymorphism/Lessones/QuizLesson.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Polymorphism.Lessones
+{
+    public class QuizLesson : Lesson
+    {
+        public int MinimumPassingScore { get; set; }
+        public override void Render()
+        {
+            Console.WriteLine($"Loading multiple-choice UI for: {Title}");
+        }
+    }
+}

Polymorphism/Lessones/VideoLesson.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Polymorphism.Lessones
+{
+    public class VideoLesson : Lesson
+    {
+        public string VideoStreamUrl { get; set; } = string.Empty;
+        public override void Render()
+        {
+            Console.WriteLine($"Starting video player for: {Title}");
+        }
+    }
+}

Polymorphism/Polymorphism.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

Polymorphism/Program.cs

+using Polymorphism;
+using Polymorphism.Lessones;
+using System;
+using System.Collections.Generic;
+
+Console.WriteLine("POLYMORPHISM — Course playlist");
+List<Lesson> playlist = new()
+{
+    new VideoLesson { Title = "C# Introduction", DurationMinutes = 15, VideoStreamUrl = "video.mp4" },
+    new QuizLesson { Title = "C# Basics Quiz", DurationMinutes = 10, MinimumPassingScore = 70 }
+};
+
+CourseManager manager = new CourseManager();
+manager.PlayCourse(playlist);
+
+
+
+
+
+
+
+