Your mat file contains a single variable (c1) which is 6x3.
It's unclear what should be plotted against what with this matrix.
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Completely unrelated, but you should prefer fullfile to strcat to build paths. Also, it's recommend to separate output variable by a , instead of just a space (matlab editor will warn you about it), so:
[f, p] = uigetfile('*.mat'); %use , to separate f and p
a = fullfile(p, f); %use fullfile which automatically adds the correct path separator for your OS
I would also recommend using much more meaningful variable names:
[basename, path] = uigetfile('*.mat');
fullname = fullfile(path, basename);
it makes the code a lot easier to understand.
