Diffing "test_1" and "test_2"

k=0;
b=a(1);
for i=1:length(a)
	for j=length(a):-1:i
l=length(a);
for i=1:l
	for j=l:-1:i
		if strcmp(a(i:j),a(j:-1:i))
			if j-i>k
				k=j-i;
				b=a(i:j);
			end
		end
	end
end