C programming help.

Need help with C programming in Linux, it is pissing me off hardcore.

I need to write a program that:
- opens a file,
- writes a command line argument to the file
- closes the file
- reopens it
-reads the contents
-prints this to the screen

Im pretty clueless on C, more of the Java type.

open();
write();
close();
open();
read();
puts();