You can store the data into a vector:
results = [];
while (condition)
code;
r = roots(x);
results(end+1) = r(4);
end
This solution isn't ideal, since the variable results keeps changing size. If you know approximately how many iteration your while loop is going to have you can preallocate the variable. For example, if you never have more than 100 runs:
results = zeros(100,1); % pre allocate
n=0;
while (condition)
code;
r = roots(x);
n = n+1;
results(n) = r(4);
end
if n == 0 % no iterations
results = [];
else % keep only real results
results = results(1:n);
end
After the while loop we only keep the true results.
Hope this helps.
