Your first program: make the computer say something

Can you make the computer print your own study plan? Start with three lines, then change one message and run it again. No programming experience is required.

Get one small program running

Install the .NET 10 SDK for your computer from the official download page, choosing the SDK section. C# is the language; the SDK supplies the tools that build and run it. Use a text editor such as Visual Studio Code to edit the file.

1. Check the tool. Open a terminal and run:

dotnet --list-sdks

A version beginning with 10.0 should be listed. If dotnet cannot be found just after installation, reopen the terminal and try again.

2. Create your practice folder. From a folder where you keep projects, run:

dotnet new console --framework net10.0 -o StudyPlanner
cd StudyPlanner

You now have a StudyPlanner folder containing a project file and Program.cs.

3. Make your first edit. Open Program.cs. Replace all its contents with the three-line printing program below and save. Each later C# block is also an independent replacement program unless a lesson explicitly says otherwise. Run the programs locally; this page has no in-page compiler.

Predict, then run

Read the instructions from top to bottom. Write the three output lines on paper before running.

using System;

Console.WriteLine("Study Planner");
Console.WriteLine("Read C# for 30 minutes.");
Console.WriteLine("One small step today.");

Now run the saved program from the StudyPlanner folder:

dotnet run

Your program’s output should be:

Study Planner
Read C# for 30 minutes.
One small step today.

The first line, using System;, lets us write Console instead of System.Console. System is a namespace: a group of related type names. The statements below it do the printing.

Console.WriteLine asks .NET to write a line of text. The text between double quotes is a string literal. The quotes mark its boundary; they are not printed. Parentheses hold the information passed to WriteLine. The semicolon ends this instruction. C# names are case-sensitive, so copy Console and WriteLine with the shown capitals.

See the stages

Edit Program.cs → Save → Build → Run → Read the output
     instructions          check/translate      execute

Saving records your edit. Building checks and translates it. Running executes the application. The dotnet run command normally builds as needed before starting. To check compilation without starting the app, use dotnet build. A successful build tells you the code follows the language rules; you still need to check whether its output meets your goal.

Change it yourself

Change the duration to 45 minutes and make the last line say Then take a short break. Save, predict all three lines, then run. Compare your attempt with this complete solution:

using System;

Console.WriteLine("Study Planner");
Console.WriteLine("Read C# for 45 minutes.");
Console.WriteLine("Then take a short break.");

If compilation fails, read the first relevant diagnostic and its line number. Check missing quotes, parentheses and semicolons. If the old message appears, confirm that you saved Program.cs and ran from this project’s folder.

Explain back: What is the difference between saving, building and running? Point to the instruction that produces each output line before moving on.

References: Microsoft — create a console app, dotnet new.