nargin, nargout (MATLAB Functions)

Return number of function arguments

Syntax

n = nargin
n = nargin(fun)
n = nargout
n = nargout(fun)

Description

In the body of a function M-file, nargin and nargout indicate how many input or output arguments, respectively, a user has supplied. Outside the body of a function M-file, nargin and nargout indicate the number of input or output arguments, respectively, for a given function. The number of arguments is negative if the function has a variable number of arguments.

nargin returns the number of input arguments specified for a function.

nargin(fun) returns the number of declared inputs for the function fun or -1 if the function has a variable number of input arguments. fun may be the name of a function, or a function handle that maps to a specific function.

nargout returns the number of output arguments specified for a function.

nargout(fun) returns the number of declared outputs for the function fun. fun may be the name of a function, or a function handle that maps to a specific function.

Examples

This example shows portions of the code for a function called myplot, which accepts an optional number of input and output arguments:

function [x0, y0] = myplot(x, y, npts, angle, subdiv)
% MYPLOT  Plot a function.
% MYPLOT(x, y, npts, angle, subdiv)
%     The first two input arguments are
%     required; the other three have default values.
 ...
if nargin < 5, subdiv = 20; end
if nargin < 4, angle = 10; end
if nargin < 3, npts = 25; end
 ...
if nargout == 0
     plot(x, y)
else
     x0 = x;
     y0 = y;
end

nargchk nargoutchk