MATLAB Programming Fundamentals - MathWorks

% Add inputs together. The number of inputs is controlled by the

% nontunable property |NumInputs|.

properties (Nontunable)

NumInputs = 3; % Default value

end

methods (Access = protected)

function y = stepImpl(obj,x1,x2,x3)

switch obj.NumInputs

case 1

y = x1;

case 2

y = x1 + x2;

case 3

y = x1 + x2 + x3;

otherwise

y = [];

end

end

function validatePropertiesImpl(obj)

if ((obj.NumInputs < 1) ||...

(obj.NumInputs > 3))

error("Only 1, 2, or 3 inputs allowed.");

end

end

function numIn = getNumInputsImpl(obj)

numIn = obj.NumInputs;

end

end

end

Run this System object with one, two, and three inputs.

addObj = AddTogether2;

addObj.NumInputs = 1;

addObj(2)

ans =

2

34 System object Usage and Authoring