% 13 characters and aligned to the right:
fprintf('%13s %13s %13s %13s \n', 'a', 'yes','async','asychronous');
% 13 characters and aligned to the left:
fprintf('%-13s %-13s %-13s %-13s \n', 'a', 'yes','async','asychronous');
fprintf('%3.10f %3.10f %3.10f %3.10f', 33.12, 5.3819, 291.210, 39.2111);
It was only the "." which is not used for the %s format.