MATLAB Programming

12 Programming Tips
Function Arguments
This section covers the following topics:
• “Getting the Input and Output Arguments” on page 12-16
• “Variable Numbers of Arguments” on page 12-16
• “String or Numeric Arguments” on page 12-17
• “Passing Arguments in a Structure” on page 12-17
• “Passing Arguments in a Cell Array” on page 12-18
Getting the Input and Output Arguments
Use nargin and nargout to determine the number of input and output
arguments in a particular function call. Use nargchk and nargoutchk to
verify that your function is called with the required number of input and
output arguments.
function [x, y] = myplot(a, b, c, d)
disp(nargchk(2, 4, nargin))
disp(nargoutchk(0, 2, nargout))
% Allow 2 to 4 inputs
% Allow 0 to 2 outputs
x = plot(a, b);
if nargin == 4
y = myfun(c, d);
end
Variable Numbers of Arguments
You can call functions with fewer input and output arguments than you have
specified in the function definition, but not more. If you want to call a function
with a variable number of arguments, use the varargin and varargout
function parameters in the function definition.
This function returns the size vector and, optionally, individual dimensions:
function [s, varargout] = mysize(x)
nout = max(nargout, 1) - 1;
s = size(x);
for k = 1:nout
12-16