Permission denied executing any gcc-compiled c program on OS X (10.8.2) Mountain Lion

When executing any C program that I have compiled with gcc from the terminal, I get a permission denied error.

To start, I have verified and repaired permissions on my drive (before doing this, the same problem was happening).

To illustrate and isolate the problem, I'll show you what happens with this ultra-simple Hello World program (with other programs, the same thing occurs):

#include <stdio.h> main() { printf("Hello World"); } 

Now, I save this to my desktop as helloworld.c. At this point, from the desktop, an ls -l returns:

total 8 -rw-r--r-- 1 michael staff 56 Mar 13 14:08 helloworld.c 

I then compile with gcc -c helloworld.c -o helloworld (I've also tried compiling without the -o flag with the same results). No warnings or errors. An ls -l now returns:

total 16 -rw-r--r-- 1 michael staff 56 Mar 13 14:08 helloworld.c -rw-r--r-- 1 michael staff 724 Mar 13 14:16 helloworld.o 

Attempting to execute the output of gcc, with ./helloworld.o returns:

-bash: ./helloworld.o: Permission denied 

Just for the sake of debugging, if I execute with sudo (sudo ./helloworld.o), it returns:

sudo: ./helloworld.o: command not found 

Now, if I attempt to set the executable flag using chmod +x helloworld.o, as was recommended on a lot of search results I've found, ls -l returns:

total 16 -rw-r--r-- 1 michael staff 56 Mar 13 14:08 helloworld.c -rwxr-xr-x 1 michael staff 724 Mar 13 14:16 helloworld.o 

However, attempting to execute with ./helloworld.o now returns:

-bash: ./helloworld.o: Malformed Mach-o file 

Now, for debugging sake, where gcc returns:

/usr/bin/gcc 

So, you can see that I am not using a third party gcc.

Does anyone know what could be the problem? I've tried searching around, but I couldn't find any working solutions. I was having this same problem earlier and have since freshly reinstalled OS X (for different reasons) and am still having this problem with a clean and organized development environment. For reference, I'm on OS X 10.8.2 and have Xcode 4.6 along with the latest version of Xcode Command Line tools (from Apple's developer website). I have not installed gcc from Homebrew or from any other third party source; it is the gcc that came with Xcode Command Line tools.

Thank you very much for your help! I really appreciate you taking your time to read, diagnose and offer your help. :)