Exercise - Discover Sort() and Reverse()

  • 10 minutes

The Array class contains methods that you can use to manipulate the content, arrangement, and size of an array. In this exercise, you'll write code that performs various operations on an array of pallet identifiers. Your code could be the start of an application to track and optimize the usage of pallets for the company.

Prepare your coding environment

This module includes hands-on activities that guide you through the process of building and running demonstration code. You're encouraged to complete these activities using Visual Studio Code as your development environment. Using Visual Studio Code for these activities will help you to become more comfortable writing and running code in a developer environment that's used by professionals worldwide.

  1. Open Visual Studio Code.

    You can use the Windows Start menu (or equivalent resource for another OS) to open Visual Studio Code.

  2. On the Visual Studio Code File menu, select Open Folder.

  3. In the Open Folder dialog, navigate to the Windows Desktop folder.

    If you have different folder location where you keep code projects, you can use that folder location instead. For this training, the important thing is to have a location that’s easy locate and remember.

  4. In the Open Folder dialog, select Select Folder.

    If you see a security dialog asking if you trust the authors, select Yes.

  5. On the Visual Studio Code Terminal menu, select New Terminal.

    Notice that a command prompt in the Terminal panel displays the folder path for the current folder. For example:

    C:\Users\someuser\Desktop>

    Note

    If working on your own PC, rather than in a sandbox or hosted environment, and you have completed other Microsoft Learn modules in this C# series, you may have already created a project folder for code samples. If that's the case, you can skip over the next step, which is used to create a console app in the TestProject folder.

  6. At the Terminal command prompt, to create a new console application in a specified folder, type dotnet new console -o ./CsharpProjects/TestProject and then press Enter.

    This .NET CLI command uses a .NET program template to create a new C# console application project in the specified folder location. The command creates the CsharpProjects and TestProject folders for you, and uses TestProject as the name of the .csproj file.

  7. In the EXPLORER panel, expand the CsharpProjects folder.

    You should see the TestProject folder and two files, a C# program file named Program.cs and a C# project file named TestProject.csproj.

  8. In the EXPLORER panel, to view your code file in the Editor panel, select Program.cs.

  9. Delete the existing code lines.

    You'll be using this C# console project to create, build, and run code samples during this module.

  10. Close the Terminal panel.

Create an array of pallets, then sort them

  1. Ensure that you have Visual Studio Code open and Program.cs displayed in the Editor panel.

    Note

    Program.cs should be empty. If if isn't, select and delete all code lines.

  2. Type the following code into the Visual Studio Code Editor:

    string[] pallets = { "B14", "A11", "B12", "A13" };

Console.WriteLine("Sorted...");
Array.Sort(pallets);
foreach (var pallet in pallets)
{
    Console.WriteLine($"-- {pallet}");
}

  3. Take a minute to review the Array.Sort(pallets); line from the previous code you added.

    Here you're using the Sort() method of the Array class to sort the items in the array alphanumerically.

  4. On the Visual Studio Code File menu, select Save.

    The Program.cs file must be saved before building or running the code.

  5. In the EXPLORER panel, to open a Terminal at your TestProject folder location, right-click TestProject, and then select Open in Integrated Terminal.

    A Terminal panel should open, and should include a command prompt showing that the Terminal is open to your TestProject folder location.

  6. At the Terminal command prompt, to run your code, type dotnet run and then press Enter.

    Note

    If you see a message saying "Couldn't find a project to run", ensure that the Terminal command prompt displays the expected TestProject folder location. For example: C:\Users\someuser\Desktop\csharpprojects\TestProject>

    You should see the following output:

    Sorted...
-- A11
-- A13
-- B12
-- B14

Reverse the order of the pallets

  1. To reverse the order of the pallets using the Array.Reverse() method, update your code as follows:

    string[] pallets = { "B14", "A11", "B12", "A13" };

Console.WriteLine("Sorted...");
Array.Sort(pallets);
foreach (var pallet in pallets)
{
    Console.WriteLine($"-- {pallet}");
}

Console.WriteLine("");
Console.WriteLine("Reversed...");
Array.Reverse(pallets);
foreach (var pallet in pallets)
{
    Console.WriteLine($"-- {pallet}");
}

  2. Focus on the line of code Array.Reverse(pallets); line from the previous code you added.

    Here, you're using the Reverse() method of the Array class to reverse the order of items.

  3. Save your code file, and then use Visual Studio Code to run your code. You should see the following output:

    Sorted...
-- A11
-- A13
-- B12
-- B14

Reversed...
-- B14
-- B12
-- A13
-- A11

Recap

Here's a few important ideas that you covered in this unit:

  • The Array class has methods that can manipulate the size and contents of an array.
  • Use the Sort() method to manipulate the order based on the given data type of the array.
  • Use the Reverse() method to flip the order of the elements in the array.

Check your knowledge

1.

Which best describes the code Array.Sort(pallets); where pallets is a string array?