Our Guide. Learn how C works

So, you’ve decided to learn C? Well, you made a good choice. This first tutorial is just how to compile a program, and kind of just learn how C works.

Depending on the compiler you want to use, the instructions vary. But, basically you will do the following steps.

For Command-Line compilers on Windows

  1. Open up Notepad or an equivalent text editor, NOT a word processor or something with fonts.
  2. Type in the following:
  3. This is the traditional Hello, World program. Save it as something like “hello.c” ( with the quotes in Notepad).
  4. Open a command prompt (or a DOS command line)
  5. Change to the directory that you saved hello.c in (using cd )
  6. Execute gcc -s hello.c -o hello.exe (For other compilers, look at your manual)
  7. If you get an error, check your typing and try again.
  8. Otherwise, type hello and press enter.
  9. You should get a Hello, World! message. Try going back and changing the message.

When you’re done experimenting, let’s look at what this means:

  • #include = Standard Input/Output Header, kind of like a screen “enabler”. This is required for the screen and the keyboard. int main(void) < = The place where the computer starts executing, therefore all statments after this line are executed.
  • printf(“Hello, World!\n”); = Prints ‘Hello, World!’ to the screen, as you may have guessed from experimenting.
  • return 0; = Return function exit code 0. Kind of advanced, skip for now, until we get to functions.
  • > = Braces mark code segments. Notice that the code segment starts at “int main”.

Double quotes (“) mark strings. So, “Hello” is a string, whereas ‘Hello’ is not. (Look-ahead fact: ‘ marks a char constant). “\n” prints a new line to the “console” (screen).

Got that? Good. Now, try to make a program that . . .

  • Prints “Hello from C!”
  • Then 4 enters

Your solution should look something like this: It’s okay like this, as well: They do the same thing.

C ignores whitespace (Tabs, spaces, enters). So, Will do the same as the first Hello, World! program.