How to fix "error using class. Not enough input arguments"?

Wrote this function code as part of a worksheet. It was working normally but all of a sudden I am getting an error message. I didn't change anything so I have no clue how this happened?

% Find the time points corresponding to the onset and offset times from the classifier
[onset, offset] = change_times(class, time);
(error comes after the line above)

% Display the number of onset/offset times determined with each classifier
length(onset);
disp(['Onset Times = ', num2str(length(onset)),])
length(offset);
disp(['Offset Times = ', num2str(length(offset)),])

Answer 1

[DGM]

You had probably shadowed the function class() with some variable by the same name -- which is something you should avoid.

which class -all

built-in (/MATLAB/toolbox/matlab/datatypes/class)
/MATLAB/toolbox/matlab/graph2d/@scribehandle/class.m      % Shadowed scribehandle method
/MATLAB/toolbox/instrument/instrument/@udp/class.m        % Shadowed udp method
/MATLAB/toolbox/instrument/instrument/@i2c/class.m        % Shadowed i2c method
/MATLAB/toolbox/instrument/instrument/@gpib/class.m       % Shadowed gpib method
/MATLAB/toolbox/instrument/instrument/@icdevice/class.m   % Shadowed icdevice method
/MATLAB/toolbox/instrument/instrument/@visa/class.m       % Shadowed visa method
/MATLAB/toolbox/instrument/instrument/@tcpip/class.m      % Shadowed tcpip method
/MATLAB/toolbox/instrument/instrument/@Bluetooth/class.m  % Shadowed Bluetooth method
/MATLAB/toolbox/instrument/instrument/@icgroup/class.m    % Shadowed icgroup method
/MATLAB/toolbox/matlab/serial/@serial/class.m             % Shadowed serial method

help class

 CLASS  Return class name of object.
    S = CLASS(OBJ) returns the name of the class of object OBJ.
  
    Possibilities are:
      double          -- Double precision floating point number array
                         (this is the traditional MATLAB matrix or array)
      single          -- Single precision floating point number array
      logical         -- Logical array
      char            -- Character array
      cell            -- Cell array
      struct          -- Structure array
      function_handle -- Function Handle
      int8            -- 8-bit signed integer array
      uint8           -- 8-bit unsigned integer array
      int16           -- 16-bit signed integer array
      uint16          -- 16-bit unsigned integer array
      int32           -- 32-bit signed integer array
      uint32          -- 32-bit unsigned integer array
      int64           -- 64-bit signed integer array
      uint64          -- 64-bit unsigned integer array
      <class_name>    -- MATLAB class name for MATLAB objects
      <java_class>    -- Java class name for java objects
 
    %Example 1: Obtain the name of the class of value pi
    name = class(pi);
 
    %Example 2: Obtain the full name of a package-based java class
    obj = java.lang.String('mystring');
    class(obj)
 
    For classes created without a classdef statement (pre-MATLAB version
    7.6 syntax), CLASS invoked within a constructor method creates an
    object of type 'class_name'.  Constructor methods are functions saved
    in a file named <class_name>.m and placed in a directory named
    @<class_name>.  Note that 'class_name' must be the second argument to
    CLASS.  Uses of CLASS for this purpose are shown below.
 
    O = CLASS(S,'class_name') creates an object of class 'class_name'
    from the structure S.
 
    O = CLASS(S,'class_name',PARENT1,PARENT2,...) also inherits the
    methods and fields of the parent objects PARENT1, PARENT2, ...
 
    O = CLASS(struct([]),'class_name',PARENT1,PARENT2,...), specifying
    an empty structure S, creates an object that inherits the methods and
    fields from one or more parent classes, but does not have any 
    additional fields beyond those inherited from the parents.
 
    See also ISA, CLASSDEF, STRUCT, SUPERIORTO, INFERIORTO.

    Documentation for class
       doc class

    Other functions named class

       Bluetooth/class    icdevice/class        serial/class    udp/class
       gpib/class         icgroup/class         tcpip/class     visa/class
       i2c/class          scribehandle/class

Since said variable is now missing and not shown in the provided code excerpt, you'll have to figure out where it went.