MATLAB: Confusion with for loop

data processingfor loop

Below is my code in which i am considering data file fb2010. At the end I have a matrix "resd". Now I want to add another three file fb2020, fb2030, fb2040. The code should be the same but including other three data files. At the end i should have four matrix like "resd"(including resd). So how to apply for loop. I tried to apply but it 's not working. Thanks in advance.
load('fb2010'); % loading the data
x = fb2010(3:1:1502,:);
% y_filt = filter(b,a,x); % filtering the received signal
y_filt= filter(b,a,x,[],2);
%%%%%%% fourier transform
nfft = length(y_filt);
res = fft(y_filt,nfft,2)/nfft;
res2 = res(:,1:nfft/2+1); %%%%taking single sided spectrum
res3 = fft(res2,[],2);
for i = 3:1:1500 %%%%dividing each row by first row.
resd(i,:) = res3(i,:)./res3(1,:);
end

Best Answer

Files={'fb2010','fb2020', 'fb2030', 'fb2040'};
for k=1:length(Files);
S=load(Files{i});
x = S.(Files{i})(3:1502,:);
....
for i = 3:1500
resd(i,:,k) = res3(i,:)./res3(1,:);
end
end