Write a Perl subroutine called get_matrix that takes as input the name of a file containing a
4x4 matrix of nucleotide-nucleotide scores and an empty array reference. On return, the array
reference should contain the contents of the matrix in the input file. For example, if the input
file matrix.txt contains

10  -1   2   1
-1   9   1   2
 2   1  11  -1
 1   2  -1  12

and the subroutine &get_matrix("matrix.txt", \@matrix) is called, then on 
return

@matrix = (	[10, -1, 2, 1],
		[-1, 9, 1, 2],
		[2, 1, 11, -1],
		[1, 2, -1, 12],
	  )

Submit your solution as a file called <firstname>HW5.pl to the teaching assistant Shikha Kaushal
(shikha.kaushal@gmail.com). Replace <firstname> with your first name.

Usman