pass command line inputs

I have a MATLAB program with somewhat following structure:

load file1.txt;

load file2.txt

a=file1(:,2);

b=file2(:,2);

g=file1(:,1);

q=file2(:,1);

for i = 1:length(a)

for j = 1:length(b)

z = a(i)*b(j);

end;

end

I have to now run this again and again for 50 files i.e. file1.txt will remain same but instead of file2.txt I have to do for 50 files like file3.txt, file4.txt, file5.txt....

how can I do it? Please help