Computing Sliding Window DFT on a digital sequece

Hi all,

I want to compute sliding window DFT of a numeric sequence. Hence I have written the code. Running the code showing an error as "Index exceeds matrix dimentions" error in x1 = x(i:i+351-1); x is the given sequence.

n = length(x);
n =1;
for i =1:1:n-1
    x1 = x(i:i+351-1);
    A = abs(fft(x1));
    S = A.^2;
    snr = max(S)/mean(S);
    y(ceil(i/h)) = snr;
    
end
plot(y)

I want plot the snr values for every window length with respect to the index values. Any help will be appreciated. How to correct it?