Determine the line of code that causes a segmentation fault?

GCC can't do that but GDB (a debugger) sure can. Compile you program using the -g switch, like this:

gcc program.c -g

Then use gdb:

$ gdb ./a.out(gdb) run<segfault happens here>(gdb) backtrace<offending code is shown here>

Here is a nice tutorial to get you started with GDB.

Where the segfault occurs is generally only a clue as to where "the mistake which causes" it is in the code. The given location is not necessarily where the problem resides.

Also, you can give valgrind a try: if you install valgrind and run

valgrind --leak-check=full <program>

then it will run your program and display stack traces for any segfaults, as well as any invalid memory reads or writes and memory leaks. It's really quite useful.

You could also use a core dump and then examine it with gdb. To get useful information you also need to compile with the -g flag.

Whenever you get the message:

 Segmentation fault (core dumped)

a core file is written into your current directory. And you can examine it with the command

 gdb your_program core_file

The file contains the state of the memory when the program crashed. A core dump can be useful during the deployment of your software.

Make sure your system doesn't set the core dump file size to zero. You can set it to unlimited with:

ulimit -c unlimited

Careful though! that core dumps can become huge.