I suppose you want to plot the inputs, and then allow the user to verify that the inputs look good before continuing? If so, a simple way is to insert a 'pause' command after the plotting is performed. That forces the user to press the space bar (after visually confirming the inputs are valid), before continuing.
doc pause
You could even make it more sophisticated, by allowing the user to select whether to continue with the function running, or jump out now. Something like this:
s = input('Are inputs valid (y/n)? ', 's');
if ~strcmpi(s, 'y'), %if not a 'y' answer,
return; %exit function now
end
