Can a C program modify its executable file?

Question

I had a little too much time on my hands and started wondering if I could write a self-modifying program. To that end, I wrote a \"Hello World\" in C, then used a hex editor

Answer 1

On newer versions of Windows CE (atleast 5.x an newer) where apps run in user space, (compared to earlier versions where all apps ran in supervisor mode), apps cannot even read it's own executable file.