Problems with running c-files

I have big problems to run my c -code files on OS X 10.5.
If I try to run my files with gcc -o file file.c and then tries to run it with ./file I get a lot of compilationserrors, it even includes errors that are comment-lines?! very strange! I never could run any c-file, so I need help now please!
I have gcc installed.
X-code does not work, if I try to open a code-file, it just output error message, that It cant run at all.

I also want to know how I run a c.ch file?

Thanks!

Sounds like you've got errors in your code. Could you post some here? If I can't help, there are a few programmers who lurk around the forums.