function c = plus(a,b);
% plus Methode  alias + Operator
% Addition fuer Klasse Bruch
a = bruch(a);
b = bruch(b);

size_a = size(a);
size_b = size(b);

if size_a == 1,
    
    a = a.*ones(size_b);
end
if size_b == 1,
    b = b.*ones(size_a);
end

size_a = size(a);
size_b = size(b);

if size_a~=size_b,
    error('dimension mismatch');
end

for k  = 1:size_a(1),
    for l = 1:size_a(2),
        
        c(k,l) = bruch(a(k,l).vz*a(k,l).zaehler*b(k,l).nenner+...
            a(k,l).nenner*b(k,l).vz*b(k,l).zaehler,a(k,l).nenner*b(k,l).nenner);
    end
end