Write a program using a loop to add all the elements of a ma
     Write a program using a loop to add all the elements of a matrix producing a scalar. Do not use the MATLAB function sum function or +.  For example, [-1 2 3; 4 5 6; -7 8 -9] SUM = 11 
  
  Solution
Code:
A=[-1 2 3; 4 5 6;-7,8,-9]
 res = 0;
 for i=1:size(A,1)
 for j=1:size(A,2)
 res = res + A(i,j);
 end
 end

