Tools

Tools#

We’ll now install Visual Studio 2022 Community, which we’ll refer to as VS, together.

For the following tutorial I used a computer with an Intel x86-64 bit processor with Windows 11 OS build 26100 (refer to System Information). Even the following steps should also work for other processors like ARM, I could not test.

VS does not support macOS. Use VirtualBox and use Windows as a virtual machine on macOS.

If the following steps do not work out for you, we can find a solution in the class. If you miss something in the steps or found an error, please create an issue or a pull request to help other students.

Visual Studio 2022 Community Edition installation#

  1. Open Microsoft Store.

  2. Search for Visual Studio and select Visual Studio Community 2022 (not Visual Studio Code). A purple white installation page will show up.

  3. Click on install. It will download the installer which is few MB. A User Account Control window will pop up and ask for permission.

  4. Click Yes. Visual Studio Installer window will pop up.

  5. Click Continue. The installer will start downloading components. In the end, a new window Installing - Visual Studio Community ... will pop up and will then show you installable components called Workloads.

  6. Scroll down Desktop & Mobile and make a tick on .NET desktop development. On the right, Installation details should show up.

  7. Leave the default components active. Click on Install. The installer will start downloading and installing. It took about 10 minutes on my computer. Look into Introduction C# until the installation ends.

    After the installation a window with Sign in to Visual Studio should pop up.

  8. You can close the Visual Studio Installer and Microsoft Store window.

  9. Go back to the VS. We will organize our code on repositories and also experiment with GitHub Copilot. So, click on Sign in with GitHub. A web-browser will pop up. Login with your credentials or create an account.

  10. During login, GitHub will ask you for permissions to exchange data with VS. Accept them. The web-browser will forward you to VS again and you will see Personalize your Visual Studio experience.

  11. You can close the formerly opened web browser window.

  12. Go back to VS. Click on the Development settings drop-down menu and select Visual C#.

    Pick a color theme that fits your environment and your taste. A study found out that a light theme is best in a well-lit environment during the day, and dark during the night.

  13. Click on Start Visual Studio. A welcome window should pop up with Open recent and Get started.

Creating a project#

  1. On the welcome window, click Create a new project. A list of templates will show up.

  2. Double click on Console App, which should be the first one on the list.

  3. We will create an online currency converter. Name the project CurrencyConverter.

  4. Activate Place solution and project in the same directory. This will create less directories which is more convenient for small projects for us as beginners.

  5. Click on Next. Additional information window will show up.

  6. You can leave the three settings in their defaults.

    If you are curious about these settings:

    1. Typically every .NET version comes with new language features. The framework can stay at the default, because we don’t need the latest language features as beginners.

    2. Do not use top-level statements: Top-level statements are in contrast to object-oriented programming (OOP). In short, top-level statements allow us to write minimal code, but OOP is more modular. We will introduce these concepts later in detail. We don’t activate this, because we will also use top-level statements.

    3. Enable native AOT publish: AOT stands for ahead of time compilation. Typically Visual C# programs are translated to an intermediate language, which is then translated to machine code first time the program is run. AOT may lead to more efficient programs in small computers and we don’t need this feature in our case.

  7. Click on Create. A progress window will pop up and after that the editor window with Program.cs containing a hello-world program.

Running a program#

  1. Click on green play button CurrencyConverter on the toolbar or F5.

    This step will start a compiler which translates the code to a format that can be executed by our computer. It will be run with debugging features. Then a console window with Hello, World! message will pop up.

console application

a program designed to be used via a text-only user interface

We will use console applications for learning fundamental programming concepts, because a console application has less complexity compared to a graphical user interface (GUI).

compiler

a computer program that translates program code written in one programming language into another

Debugging a program#

debugging

the process of finding the causes and possible fixes for bugs

When our programs get more complicated, debugging will be very useful to find the bugs. In debugging mode, the code will pause at the program line where the first error happened at will give us the opportunity, e.g., which values the variables have to inspect the crime scene like a detective 🕵️.

To learn how debugging works, copy the following code and replace Program.cs on your editor:

1Console.WriteLine("Before");
2int[] numbers = { 1, 2, 3 };
3Console.WriteLine(numbers[5]);
4Console.WriteLine("After");

  1. Press F5

  2. The program should stop at third line. VS is not debugging mode and will show you actions like ⤍/ (show next statement), stop (stop debugging).

    VS should show you the error cause Index was outside the bounds of the array.. How can this happen? Let us overlook for a moment that we initialized the array with three elements for the sake of this tutorial. We should check the contents of the array numbers.

    _images/debugging-numbers-array.png

    Fig. 1 When we hover our mouse over a data structure in debugging mode, we can see information about its contents. When we click on the ▾ symbol, we can further expand and see actual contents.#

    In debugging mode, we can inspect contents of data structures.

  3. Hover your mouse over numbers in the editor, you see first the size of the array as in Fig. 1. Now the error cause should be clear and you can fix your code, e.g., using the right index or making sure that the value that [5] points to exist.

  4. Stop debugging by using stop.

  5. On the right of the last button, you will see another play button ▷, which stands for Start Without Debugging. Our program will start faster and execute probably also faster in this mode, because debugging features also affect performance.

    We don’t care about performance right now and can simply use F5 for starting our program.

  6. Close the console by pressing a key. You should be back on your editor.

Saving our code on a repository#

Now we will store our code on a repository which is an important tool in version control systems.

version control

the software engineering practice of controlling, organizing, and tracking different versions in history of computer files; primarily source code text files, but generally any type of file.

repository

(in context of version control systems) a data structure that stores metadata for a set of files or directory structure. The main purpose of a repository is to store a set of files, as well as the history of changes made to those files.

Keeping a history of changes is helpful if we or someone else who also work in the project would like to understand changes in the project which is useful for collaboration. Keeping a history helps also to roll changes back if something does not work as intended.

Keeping projects in a repository is also helpful to collaborate and share code. You will use it later to share or submit your projects. You probably already downloaded something from the code forges GitHub or GitLab.

code forge

a web interface to a version control system

Note that repositories are not only good for program code but for all kinds of text-based files.

We had already logged in on GitHub with VS, so let us create our first repository on GitHub.

  1. On the right you should see a sidebar with the title GitHub Copilot Chat. On the bottom of that sidebar, click on the tab Git Changes. You should now see Git Changes tab.

  2. Click on Create Git Repository. A new window with the same name will pop up.

  3. If you want to share your project, e.g., for submitting homework using a URL:

    • activate Add a README.md to add information about your project.

    • Change visibility to Public.

  4. Click Create and Push. You may be asked whether you want to save your files before pushing.

    During this process your repository will be created.

    If you get the error error setting cerificate file: ..., refer to here.

    If you want to push your code again, e.g., in case of an error, then use ⬆️ on the Git bar.

    If successful, you should see ℹ️ Successfully pushed ....

  5. Now check how your pushed code look like on the code forge GitHub by clicking on ... on the Git changes bar and clicking on Open in Browser or simply browsing https://github.com/*YOUR-USERNAME*/CurrencyConverter.

    You should see something similar to:

    user and user  Add project files.   ... 2 Commits

.gitattributes
.gitignore
CurrencyConverter.csproj
CurrencyConverter.sln
Program.cs
README.md

    • Files beginning with .git are for Git configuration. These are templates from VS that we don’t need to understand right now.

    • *.csproj and *.sln are project and solution files. VS takes care of them when we save our project.

    • Program.cs is our source code

    • README.md contains information about our project that we will fill with info later.

source code

a plain text computer program written in a programming language

README

contains info about files in a directory of computer software. It is a form of documentation.

On GitHub, click on the 2 Commits.

Tip

If you cannot find a word or identifier from this tutorial immediately on the web page, use Ctrlf to search for it.

changeset

list of differences between two successive versions in a repository

commit

the operation of committing such a changeset to the repository

VS automatically created two commits and added some information message to each commit. When we use repositories we make our changes in commits.

Ideally each commit should be a set of changes that adds one or many describable feature like improved user name handling or added robot program. The advantage is that the programmer can roll back changes if these features led to problems later. But often people don’t want to put so much structuring work and use a repository as a diary and commit code at the end of the day.

You see that the commits are associated with user which should be the username of your operating system account. Let us change it to our GitHub username:

  1. Click on the top menu on Git -> ⚙️ Settings. Options window should pop up.

  2. Enter your GitHub username and email.

  3. To test, make a small change in your code like adding a new line to your code (Enter).

  4. Now save your file using Ctrls. You should see a change on the Git bar in the Changes list. This will list your changes compared to the last commit.

    Without any change, we cannot create a commit

  5. On the Git Changes bar, write a test message like testing new username onto the box Exter a message.

  6. Click on Commit All. You should see Commit ... created locally, which means that we created a commit on our local project, but the code forge is not aware of our changes right now.

    If you see ℹ️ Nothing to commit, then you probably did not change any file.

    _images/github-testing-new-username.png

    Fig. 2 GitHub commit after setting the username correctly#

  7. Click on ⬆️ to synchronize our repository with the repository on the code forge GitHub.

  8. Check the commits on your web web browser. Now you should see your username like in Fig. 2.

Improvement suggestions with the Screwdriver () and traditional C# style#

_images/screwdriver-on-currencyconverter-code.png

Fig. 3 Screwdriver gives typically improvement suggestions#

On the default template code, you should see the screwdriver icon on the top. This gives you typically improvement suggestions that you can use as seen in Fig. 3.

  1. Click on the and click on the suggestion about Convert to 'Program.Main' style program. You will see additional code that wraps the original code as follows:

    internal class Program
{
   private static void Main(string[] args)
   {
      Console.WriteLine("Hello, World!");
   }
}

  2. Press F5. You should see the same program output.

This is the traditional C# code that shows the actual structure of a top-level program. Top-level means the entry point (to the program) – the functions that first get executed when we start a program.

But why would you write code that is serves no functional purpose? As long as we don’t have to use this functionality somewhere else, there is no need to write class declarations. But as software evolves with time, this functionality may become a component of a more complex program, which means that the top-level may change. In this case we have to introduce such a class structure. Nevertheless, we will prefer top-level statements to traditional top-level C# code to simplify our code.

If you encounter C# code on the internet, you may see both versions, so it is important to know the difference.

Last but not least, suggestions may not always improve your code. So be critical.

A currency converter with input & Code style#

Let us finally try a more meaningful program — a currency converter. We will also talk about code style Replace Program.cs with the following:

 1using System.Text.Json;var client=new HttpClient ( );
 2string json= 
 3await client.GetStringAsync("https://api.frankfurter.dev/v1/latest?base=DKK");
 4var dkk_in_eur = JsonDocument.Parse(json).RootElement.GetProperty("rates").GetProperty("EUR").GetDouble();
 5
 6Console.WriteLine(      $"1 DKK = {dkk_in_eur} EUR");
 7Console.Write("Enter amount in DKK: ");
 8
 9var dkk_amount = Convert.ToDouble(Console.ReadLine());
10var eur_amount = dkk_amount * dkk_in_eur;
11Console.WriteLine($"{dkk_amount} DKK = {eur_amount:F2} EUR");

  1. Run the program using F5.

  2. Try the program with an input.

Now let us speak about code style. Look at the highlighted lines. Does something catch your eye? Think about it some seconds before you continue.

If you have the feeling that the code is not easy to read, then you are on the right track! When we write ordinary text, then we pay attention that the words that belong to a sentence belong to the same line unless we continue on the next line as follows:

The program converts between DKK and EUR.

Now look at the following:

The
program
converts
between DKK and EUR.

Both text have the same meaning, but the former is more readable. When we write programs we also pay attention to programming style.

programming style

also known as coding style, are the conventions and patterns used in writing source code, resulting in a consistent and readable code

The style mistakes in the first lines are:

  1. A typical statement ends with a semicolon ;. Every statement is typically on a separate line.

  2. We use spaces around =.

  3. We don’t leave spaces after a function name and between empty parentheses: HttpClient().

  4. We typically separate lines that logically do not belong together, e.g.,:

    using System.Text.Json;

var client = new HttpClient();

    Additionally we could also separate Console.WriteLine functions for better readability, as they print something on the terminal.

    A similar analogy would be writing paragraphs in written text.

We humans may not behave consistently and make mistakes but machines typically do more consistent work. Fortunately, editors can automatically format the code for us:

  1. Click on the first line. An icon similar to idea-lightbulb should appear in the beginning of the line. Click on idea-lightbulb, then a menu will come up.

  2. Click on Fix Formatting. You will see that most of the style issues are fixed, but not all. The formatter cannot understand everything in our code, so we have to still may attention to writing “paragraphs” in our code.

Instead of formatting our code every time manually, let us format our code whenever we save our project:

  1. Tools -> Options -> Text Editor -> Code Cleanup

  2. Activate Run Code Cleanup profile on Save and click on OK.

  3. Save your document Ctrls. You should see that the formatting on line 7 is fixed too.

Using Copilot as an assistant#

A GPT can support us better than editor assistance tools during coding, because a GPT can have a deeper understanding. As an example, we will use the GPT Copilot for formatting and explaining the code.

  1. On the bottom of the right bar, click on the GitHub Copilot Chat.

  2. Ask Copilot: format code. Here is the output from ChatGPT 4.1:

    using System.Text.Json;

var client = new HttpClient();
string json = await client.GetStringAsync("https://api.frankfurter.dev/v1/latest?base=DKK");
var dkk_in_eur = JsonDocument.Parse(json)
    .RootElement
    .GetProperty("rates")
    .GetProperty("EUR")
    .GetDouble();

Console.WriteLine($"1 DKK = {dkk_in_eur} EUR");
Console.Write("Enter amount in DKK: ");
var dkk_amount = Convert.ToDouble(Console.ReadLine());
var eur_amount = dkk_amount * dkk_in_eur;
Console.WriteLine($"{dkk_amount} DKK = {eur_amount:F2} EUR");

    We see that ChatGPT not only added a nice wrapping on the fifth line (VS can also do this with idea-lightbulb, but it is manual anyway) but also separated our code logically by separating the header (using System...), getting and parsing the data (second block) and outputting the data (last block).

  3. Apply these suggestions by clicking Apply on the top of the suggestions. VS may ask you to accept some changes with Tab.

  4. Try the program again to be sure that it still works.

You probably used ChatGPT for explaining you things. Let us try this too.

  1. Ask Copilot: this is my first programming language. Explain me the code. You should see explanations line by line.

Tip

One of the learning goals of this course is to identify and explain core programming concepts without a GPT to be able to criticize the output of a GPT. I recommend you to write the programs yourself and ask the GPT only for getting feedback, improvements or explanations.

Lastly let us finish this project for now by writing minimal documentation to README.md and committing our changes:

  1. On the bottom of the right bar, click on Solution Explorer tab. Open README.md`.

  2. Under the title # CurrencyConverter, write, e.g., An online currency converter from DKK to EUR.

  3. Save README.md.

  4. Go to the Git Changes tab.

  5. Try to think about a message which summarizes your commit before you continue to read.

    I came up with: initial currency converter

    Now try generating a commit message using Copilot by pressing the pen icon similar to 🖊️. I got the following message:

    Add DKK to EUR conversion functionality

Updated `Program.cs` to implement currency conversion from Danish Krone (DKK) to Euro (EUR) using an external API. The program now fetches exchange rates, prompts the user for an amount in DKK, and displays the equivalent amount in EUR. 

Modified `README.md` to include a description of the program as an online currency converter.

    This is more detailed and correct. You have to choice whether you accept it or not.

  6. Commit your changes.

  7. Push your changes.

Summary#

You installed and used VS and its helpful components on example code, congratulations 🎉! Now you are ready to dive deeper in C# coding.

Overview of the shortcuts we have used#

Ctrls

save project

F5

compile and run project in debugging mode

Ctrlf

search
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