README.md

Topic 0: Hello World

This is just simple tutorial on how to compile and run a C source code in the command line. In this tutorial you will learn the following:

• Basics of compilation process
• C Comments
• Basics of C source file structure.
• Basics of C include file.

The source codes for this tutorial is the hello_world.c and the example_include.h. Open the source codes and read the comments to learn more about it. To compile and run the tutorial, open a command line window (powershell). If you are using visual studio code, from the menu toolbar, click terminal->New Terminal. A new terminal will open within the Visual studio code window.

Compilation

To compile the program, you can use gcc. You have installed gcc in the overview. The simplest way to compile using gcc is in this format:

gcc <file to compile>

There are other options to the gcc.

gcc hello_world.c

This will generate an error. Compilers will show you the syntax errors during compilation. In this case the syntax error is the missing semicolon after in the line return 0. The syntax error usually points the line where the error is found. Just add the semicolon (e.g return 0;) and re-run the compilation command. This should produce no errors or warnings.

If you check your directory, a file named a.exe has been created. This is the executable file that was generated from source code you compiled. You can run this program from the terminal by running the following:

.\a.exe

This will print some texts in the terminal.

Exercises

Modify the source code

Try to add a code that will print your name. Since you modified the code, you will need to recompile it.

Set the filename of the compiled executable file

Use the -o <desired filename> switch of the gcc compiler. Read more about this here. You should be able to build the executable file in your selected filename.

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This ends the Topic 0: Hello World.
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