Build and Run

The computer cannot run source code directly. We need a compiler or interpreter. Dotnet uses a combination of both, with your source code being compiled into an intermediate code that is then run within a “just in time” (JIT) compiler at runtime. Luckily, all of this is detail abstracted away for us by the dotnet tool.

To build and run a program we need a terminal — to help you there is one built into VS Code! Press Ctrl-~ and a terminal should open at the bottom of your window. You can also access this using Ctrl-Shift-P (or Cmd-Shift-P on macOS), typing terminal, and selecting Terminal: Create New Terminal from the options shown.

Tip

Learn the shortcuts - these will help save you time. With programming tools, most things can be done from the keyboard without needing to use your mouse or touch screen.

Now you can build and run your program.

Action	Command	Description
Build your program	dotnet build	Compile your C# program, so it is ready to run.
Build and run your program	dotnet run	This will build and then run your program.

You would run these as:

dotnet build
dotnet run

The first step, dotnet build, will compile the code, listing any errors you may have. dotnet run will then execute your program and show you the message you printed to the terminal.

Tip

You can actually skip dotnet build. The dotnet tool will check your project when you run it. If any of the files have changed, it will build it before it runs it. This isn’t something all languages will do, but it is a shortcut we can use with dotnet.

With these simple commands you can create a project, build it, and run it, all from the terminal.

• dotnet new console - create a new C# terminal project in the current working directory.
• dotnet build - compile the project in the current working directory (can be skipped).
• dotnet run - build if needed, then execute your program.

Before we wrap up, let’s look at really useful tool called the debugger, and the SplashKit library that makes it easier to build more interesting programs.