finish lecture 12, add invert to special slide snippets

.vscode/markdown.code-snippets

@@ -62,13 +62,13 @@
 		"prefix": "extra",
 		"body": [
 			"## Extra: $0",
-			"<!-- _class: extra -->",
+			"<!-- _class: \"extra invert\" -->",
 		],
 		"description": "Extra slide colors"
 	},
 	"exercise slide" : {
 		"scope": "markdown",
-		"prefix": "exercise",
+		"prefix": "\"exercise invert\"",
 		"body": [
 			"## Exercise $0.",
 			"<!--_class: exercise -->",

12. Files and Streams.md

@@ -1,295 +1,233 @@
-# Files and Streams
-
-![](imgs/12%20Files%20and%20Streams_0.png)
-
 ---
-
+marp: true
-# Overview
+paginate: true
-
+math: mathjax
-Files and Streams
+theme: buutti
-
+title: 12. Files and Streams
-Reading from a File
+---
-
-Writing to a File
-
-JSON Serialization
-
-JSON Deserialization
 
 # Files and Streams
 
-The .NET library contains classes for manipulating files and directories
+<!-- headingDivider: 5 -->
-
+<!-- class: invert -->
-The FileStream class contains methods for read and write operations for files
-
-The goal is usually to turn the data in your code into an outside resource, such as a .txt file, and vice versa
-
-Application Code
 
-Stream writer / reader
+## Overview
 
-String, int, ...
+* Files and Streams
+* Reading from a File
+* Writing to a File
+* JSON Serialization
+* JSON Deserialization
 
-FileStream object
+## Files and streams
 
-.txt, .csv, .png, ...
+* The .NET library [contains classes](https://learn.microsoft.com/en-us/dotnet/api/system.io?view=net-7.0
+) for manipulating files and directories
+* The `FileStream` class contains methods for read and write operations for files
+* The goal is usually to turn the data in your code into an outside resource, such as a .txt file, and vice versa
 
----
+![](imgs/12%20Files%20and%20Streams_0.png)
 
-https://learn.microsoft.com/en-us/dotnet/api/system.io?view=net-7.0
 
-# Using the File Class
 
-To get started, add the following namespace to your project:
+## Using the `File` Class
 
+* To get started, add the following namespace to your project:
+  ```csharp
   using System.IO;
-
+  ```
-System.IO provides basic directory and folder support, and allows reading and writing to files and data streams
+* `System.IO` provides basic directory and folder support, and allows reading and writing to files and data streams
-
+* Check if a file exists with the `.Exists()` method:
-Check if a file exists with the .Exists() method:
+  ```csharp
-
   string path = @"C:\\Users\\Public\\TestFolder\\TestFile.txt";
-
   if (!File.Exists(path))
-
   {
-
     Console.WriteLine($"The file {path} does not exist.");
-
   }
+  ```
 
----
+## Reading from a file
-
-https://learn.microsoft.com/en-us/dotnet/api/system.io?view=net-7.0
-
-# Reading from a File
-
-Get the entire document as a string with File.ReadAllText
-
-Get all lines of a document as a string array with File.ReadAllLines
 
+* Get the entire document as a string with `File.ReadAllText`
+* Get all lines of a document as a string array with `File.ReadAllLines`
+  ```csharp
   string path = @"C:\\Users\\Public\\TestFolder\\TestFile.txt";
-
   if (!File.Exists(path))
-
   {
-
     Console.WriteLine($"The file {path} does not exist.");
-
   }
-
   else
-
   {
-
     var allLines = File.ReadAllLines(path);
-
     foreach (string line in allLines)
-
       Console.WriteLine(line);
-
   }
+  ```
 
-# Writing to a File
+## Writing to a file
 
-Writing to a file is done with File.WriteAllText and File.WriteAllLines methods:
+* Writing to a file is done with `File.WriteAllText` and `File.WriteAllLines` methods:
-
-string path = @"C:\\Users\\Public\\TestFolder\\TestFile.txt";
 
+```csharp
+string path = @"C:\Users\Public\TestFolder\TestFile.txt";
 string[] lyrics = new string[]
-
   {
-
     "Hello",
-
     "Is it me you're looking for",
-
     "I can see it in your eyes",
-
     "I can see it in your smile"
-
   };
 
 if (File.Exists(path))
-
-{
-
   File.Delete(path);                 // If file exists, deletes the old file
 
-}
-
 File.WriteAllLines(path, lyrics);    // Creates a new file with lyrics
+```
 
-# Exercise 1: A Simple Parser
-
-Create a console application which keeps asking the user for a string. Each string is added into a list of strings.
 
-If the user returns an empty string, the program asks for a path to a .txt file.
+## Exercise 1: A simple parser
+<!--_class: exercise -->
 
-If the file exists, its contents are replaced with each string written to a separate line. If not, a new file with the contents is created.
+1. Create a console application which keeps asking the user for a string. Each string is added into a list of strings.
+2. If the user returns an empty string, the program asks for a path to a .txt file.
+3. If the file exists, its contents are replaced with each string written to a separate line. If not, a new file with the contents is created.
 
-# JSON Serialization
+## JSON
 
-* JSON (JavaScript Object Notation) is a way to represent code objects in text form, a "data-interchange format"
+* [JSON](https://www.json.org/json-en.html) (JavaScript Object Notation) is a way to represent code objects in text form, a "data-interchange format"
 * Enables reading and writing series of objects into a text file
 * Consists of two types of structures
   * Objects, or unordered name-value pairs
   * Ordered lists of values
 * Language-independent, although the JSON notation resembles the C-family of languages (C#, Java, JavaScript etc.)
----
 
-https://www.json.org/json-en.html
 
-# JSON Serialization (continued)
+
+### JSON Serialization: set-up
 
 * .NET projects do not directly support JSON serialization
-* A  __NuGet package__  for that exists, called  __Newtonsoft.Json __
+* A  *__NuGet package__*  for that exists, called  `Newtonsoft.Json`
-* Install the package from  _Tools _ ->  _NuGet Package Manager_  -> M _anage NuGet Packages for Solution…_
+* Install the package from  _Tools > NuGet Package Manager > Manage NuGet Packages for Solution…_
   * Select _Browse_
   * The _Newtonsoft.Json_  should be the topmost package. If not, search for it from the search bar
   * Select the package, check the checkbox next to  _Project_ and click  _Install_
 
-You can  __serialize __ an object (e.g. a list) into a JSON string with the JsonConvert.SerializeObject() method:
+### JSON Serialization: an example
 
-class Product
+You can *__serialize__* an object (e.g. a list) into a JSON string with the `JsonConvert.SerializeObject()` method:
 
-{
+<div class='columns21' markdown='1'>
+<div markdown='1'>
 
+  ```csharp
+  class Product
+  {
     public int Id { get; set; }
-
     public string Name { get; set; }
-
   }
-
   static void Main(string[] args)
-
   {
-
     List<Product> products = new List<Product>
-
     {
-
       new Product{Id=1, Name="Awesome Product"},
-
       new Product{Id=2, Name="Terrible Product"}
-
     };
-
     string jsonString = JsonConvert.SerializeObject(products);
-
+    File.WriteAllText(@"C:\Users\OMISTAJA\source\repos\Example\Products.json", jsonString);
-File.WriteAllText(@"C:\\Users\\OMISTAJA\\source\\repos\\Example\\Products.json", jsonString);
-
   }
+  ```
+
+</div>
+<div markdown='1'>
 
 The contents of the output file Products.json are as follows:
 
 ![](imgs/12%20Files%20and%20Streams_1.png)
 
-# JSON Deserialization
+</div>
+</div>
 
-__Deserializing __ the contents of a JSON file into an object in your program can be done with the JsonConvert.DeserializeObject() method:
+## JSON Deserialization
 
-string json = File.ReadAllText(
+*__Deserializing__* the contents of a JSON file into an object in your program can be done with the `JsonConvert.DeserializeObject()` method:
 
-@"C:\\Users\\Johannes\\source\\repos\\Luentoesimerkit\\Luentoesimerkit\\db.json");
+```csharp
+string json = File.ReadAllText(
+  @"C:\Users\OMISTAJA\source\repos\Luentoesimerkit\Luentoesimerkit\db.json");
 
 List<Product> deserializedProducts = new List<Product>();
-
 deserializedProducts = JsonConvert.DeserializeObject<List<Product>>(json);
 
 foreach(Product product in deserializedProducts)
-
 {
-
   Console.WriteLine(product.Name);
-
 }
+```
 
-# Exercise 2: Serializing Your Classes
+## Exercise 2: Serializing Your Classes
-
+<!--_class: exercise -->
-Create a class Note with the properties int Id, DateTime TimeStamp and string Text.
-
-Create a main loop that keeps asking the user for a new note.
-
-After the user has entered each note, a new Note object is created with a running Id (1, 2, 3…), TimeStamp set to current time and Text is the inputted note. Each new note is added to a list of notes, allNotes.
 
-Every time a new note is submitted, the allNotes list is serialized into a json file, "notes.json". Set the path to the current project path (you can get the path by right-clicking the project in solution explorer and selecting "Copy Full Path". Remember to change the file name!)
+1. Create a class `Note` with the properties `int Id`, `DateTime TimeStamp` and `string Text`.
+2. Create a main loop that keeps asking the user for a new note.
+3. After the user has entered each note, a new `Note` object is created with a running `Id` (1, 2, 3…), `TimeStamp` set to current time and `Text` as the inputted note. Each new note is added to a list of notes `allNotes`.
+4. Every time a new note is submitted, the `allNotes` list is serialized into a json file `notes.json`. Set the path to the current project path (you can get the path by right-clicking the project in solution explorer and selecting _Copy Full Path_. Remember to change the file name!)
 
-# FileStream
+## Extra: FileStream
-
+<!-- _class: extra -->
-The files have to be opened before read/write and closed after
-
-Behind the scenes, the ReadAll... and WriteAll… methods automatically do the opening and closing, as described in the Microsoft documentation:
 
+* The files have to be opened before reading or writing and closed after
+* Behind the scenes, the `ReadAll...` and `WriteAll...` methods automatically do the opening and closing, as described in the Microsoft documentation:
   ![](imgs/12%20Files%20and%20Streams_2.png)
+* Writing to or reading only a part of the file requires opening and closing the file manually
+* This creates a *__FileStream__* object that can be used for accessing parts of the file
 
-Writing to or reading only a part of the file requires opening and closing the file manually
+## FileStream (continued)
-
+<!-- _class: "extra invert"  -->
-This creates a  __FileStream __ object that can be used for accessing parts of the file
 
-# FileStream (continued)
+* When inserting string data into a file, it needs to be converted into bytes
-
-When inserting string data into a file, it needs to be converted into bytes
-
-string path = @"C:\\Users\\Public\\TestFolder\\TestWriteFile.txt";
 
+```csharp
+string path = @"C:\Users\Public\TestFolder\TestWriteFile.txt";
 int nOfLines = 4;
-
 FileStream fs = null;
-
 if (!File.Exists(path))                                       // If file does not exist
-
   fs = File.Create(path);                                     // create a new file and open it
-
 else                                                          // If file exists
-
   fs = File.OpenWrite(path);                                  // open an existing file for writing
-
 for (int i = 0; i < nOfLines; ++i)
-
 {
-
   string input = Console.ReadLine() + "\\n";                  // Read user input, add newline
-
   byte[] byteInput = new UTF8Encoding(true).GetBytes(input);  // Get the string as a sequence of bytes
-
   fs.Write(byteInput, 0, byteInput.Length);                   // Write the bytes at the end of the file
-
 }
-
 fs.Close();                                                   // Close the file
+```
 
-# The Using Statement
+## Extra: The `using` statement
-
+<!-- _class: "extra invert"  -->
-From the Microsoft Documentation about the FileStream class:
 
+* From the Microsoft Documentation about the FileStream class:
   ![](imgs/12%20Files%20and%20Streams_3.png)
+* This means that wrapping the file handling in an  `using` block handles the opening and closing of the stream for you
 
-This means that wrapping the file handling in an  __using __ block handles the opening and closing of the stream for you
+---
+<!-- _class: "extra invert" -->
 
 The following reads the first 20 characters of a file and prints them to the console
 
-string path = @"C:\\Users\\Public\\TestFolder\\TestFile.txt";
+```csharp
-
+string path = @"C:\Users\Public\TestFolder\TestFile.txt";
 int nOfBytesToPrint = 20;
-
 byte[] byteArray = new byte[nOfBytesToPrint];
 
 if (!File.Exists(path))
-
   Console.WriteLine($"The file {path} does not exist.");
-
 else
-
   using (FileStream fs = File.OpenRead(path))
-
   {
-
     fs.Read(byteArray, 0, nOfBytesToPrint);
-
   };
-
 // No need to close the file since it was handled inside of a using block
 
 Console.WriteLine(Encoding.UTF8.GetString(byteArray, 0, byteArray.Length));
-
+```