%% Math 230, Spring 2011
%% Function for Problem 7 in Homework 10

function [C,s] = SqrDiff(A,B);

% check if sizes of A and B are the same. If yes, proceed.
if size(A)==size(B)
  C = A.^2 - B.^2;
  s = sum(sum(C));
else
  disp('Sizes of A and B not same. Quitting ...');
end


%% OUTPUT FROM MATLAB

>> m=4;n=5;
>> A = round(10*rand(m,n))
A =
     8     6    10    10     4
     9     1    10     5     9
     1     3     2     8     8
     9     5    10     1    10
>> B = round(5*rand(m,n))
B =
     3     3     3     1     3
     0     4     1     0     2
     4     4     4     0     5
     5     2     0     4     0
>> [C,s] = SqrDiff(A,B)
C =
    55    27    91    99     7
    81   -15    99    25    77
   -15    -7   -12    64    39
    56    21   100   -15   100
s =
   877
>> m=3;n=7;
>> A = round(5*rand(m,n))
A =
     2     4     2     4     3     2     3
     2     1     3     1     1     5     1
     4     2     4     3     1     2     4
>> B = round(5*rand(m,n))
B =
     1     4     1     4     1     1     2
     3     5     1     1     5     1     2
     3     3     1     4     2     3     4
>> [C,s] = SqrDiff(A,B)
C =
     3     0     3     0     8     3     5
    -5   -24     8     0   -24    24    -3
     7    -5    15    -7    -3    -5     0
s =
     0