I am really new to C, so I am sorry if this is a absolute beginner question, but I am getting a segmentation error when I am building large array, relevant bits of what I am
You're consuming too much stack. The limit is platform dependent.
The exact limit depends on the OS. These limits can be changed to some extent on some operating systems .
For large amounts of memory, you should be using the head with malloc and/or calloc (and free).
malloc
calloc
free