1. I have a segmentation fault when I try to run a program I have written in Fortran. The compiler I used is gfortran. What typically causes a segmentation fault, and how do I find where the problem is? I know I should use a debugger, but I don't know which debugger I should use, how to get it, or how to use it (I don't know whether it is Fortran 95, 03 or 08--how do I find out?).