command to stop program if there is no enough input parameters?

I made some function file that plot x versus y with extrema max min etc... I need to find command that will stop program if there is not enough input parameters. First input paremeter is "x" and second "y", and there is few more input parameters but they arent important now.

if nargin <2 || isempty(x0)
   disp('Must enter two input parameters for plot.')
end

Program will display message, but what I have to do to make program stop if there arent at least 2 input parameters?

Answer 1

[Julia]

Hi,

include the return command to stop your program.

http://www.mathworks.com/help/matlab/ref/return.html

Answer 2

[Guillaume]

The normal way to stop a program when a precondition is not met is to issue an error. Not only does it stop the program, it also displays the message in red.

if nargin < 2 || isempty(x0)
  error('Must enter two input parameters for plot.');
end

Note that there are a number of functions in matlab that can help you validate your preconditions and throw an error when these are not met, for example validateattributes, validatestring, narginchk and nargoutchk. In your particular case

narginchk(2, 2);
validateattributes(x0, {'numeric'}, {'nonempty'});

Answer 3

[Nikola]

OK, error command do what I need. Thanks