function [C]=matrix_product(A,B);
[n,m]=size(A);
[p,q]=size(B);
if m==p
    % we can compute the product
   C=zeros(n,q); % initializes a variable of 0, of size (n,q)
   for i=1:n
       for j=1:q
           % we compute c_ij
           s=0;
           for k=1:m
               s=s+A(i,k)*B(k,j);
           end
           C(i,j)=s;
       end
   end
    
else
    warning('The inner dimensions do not agree');
    C=[];
end