C Programming Part 1

Basic computer programming things to know:
C is a low-level computer programming language that is mainly used for system programming.

compiler - a program that converts source code (the code a person creates) into object code (the code a computer understands).

linker - a program that combines object code with other object codes or libraries to create an executable program.

Go here and download MS Visual C++ 2008 Express Edition to obtain a C compiler for Windows. There are many other compilers out there that will also work.

Here is a compiler for the Linux OS.

Use notepad, vi or any other simple text editor (if you use MS Word, make sure to save as a text file) to create your source code.

You will be using the Windows command line (from Visual Studio 2008 Command Prompt) or the Linux terminal window to compile and run your codes.

Here is a list of commands for the MS Visual 2008 C++ command line:(the outside quotation marks are not part of the command)

MS Visual 2008 C++ Command Line

Commands	Description
cd dir_name	changes directory to dir_name (cd \ brings you to root folder)
mkdir dir_name	creates a directory with the name dir_name
dir	lists everything in directory
cls	clears screen
notepad file_name.c	opens file_name.c in notepad (if file doesn't exist, it will create one)
type file_name.c	shows you the content of file_name.c
cl file_name.c	compiles and links file_name.c
file_name	runs the file file_name.exe
move file_name dir_name	moves the file, file_name, into the directory dir_name
del file_name	deletes the file file_name
(Hold Ctrl and C)	breaks out of the program (useful when stuck in an infinite loop)

Here is a list of commands for the Linux terminal window:

Linux Terminal Window Commands

Commands	Description
cd dir_name	changes directory to dir_name (cd \ brings you to root folder)
mkdir dir_name	creates a directory with the name dir_name
dir	lists every file in directory
vi file_name.c	opens file_name.c in vi editor (if file doesn't exist, it will create one)
:w (vi editor command)	saves the file
:q (vi editor command)	quits the vi editor
cat file_name.c	shows you the content of file_name.c
cc -o name file_name.c	compiles file_name.c and creates an output file called name
./name	runs the file called name

Basic C Program, Hello World:

#include <"stdio.h"> // Quotation marks are not supposed to be in this line of code.
main()
{
printf("hello world\n");
}

The simple code above will show the text hello world.

• The #include <"stdio.h"> (no quotation in real code - blogger problem) is used to add the standard input/output library (a library is just preprogrammed keywords/commands) to the code.
• The // indicates a comment. Anything to the right of the // is not considered part of the code.
  
• Every C file must include a main() {}. It is called the main function and it is the first place the computer looks at when running the code.
• The printf is just a function that displays whatever is provided inside the parenthesis.
• The quotation marks inside the parenthesis indicates that hello world is a string (ordered sequence of characters).
• The \n indicates that a new line is to be created next.
• The ; indicates the end of the statement.