The very first one in this documentation: http://www.mathworks.com/help/matlab/matlab_oop/getting-familiar-with-classes.html
The class is:
classdef Basic
Your error message doesn't look correct compared with the code, whichever your missing a class constructor (as is mentioned at the half way down the help link):
classdef BasicClass
properties
Value
end
methods
% Class constructor -> which you can pass pi/3 into.
function obj = BasicClass ( varargin )
if nargin == 1
obj.Value = varargin{1};
end
end
% Your Methods
function r = roundOff(obj)
r = round([obj.Value],2);
end
function r = multiplyBy(obj,n)
r = [obj.Value] * n;
end
end
end