Macintosh...DunDunDunDA!!!!! Project Builder

I've been using project builder ( a macintosh IDE) to start learning C but I keep running into the same problem.
When I copy and paste .c source code from the C tutorials (on this site) into project-builder they compile and link just fine but when the run window opens they don't run. Then when I close the windows, the whole application shuts down. I only have this problem with certain websites' source code.
Can anyone tell me if I can get around this and if so....How? I'm a total novice at all this stuff so I'm probably just overlooking something simple.

Oh BTW I use the Standard Tool option as a project type and then I write the souce code examples in the main() file window.

Thanks,

Mildred

Have you noticed anything particularly different about the code that doesn't run properly to the code that does?

We could help you out if you paste the code here ..