D'Anjou asked . 2023-08-03

Why is calling a superclass constructor after a use of the object not allowed?

classdef superclass
    
    %% PROPERTIES
    properties
        x;
        y;
    end
    
    %% METHODS
    methods
        function obj = superclass(x,y)
            % Initialize the properties
            obj.x = x;
            obj.y = y;
        end
    end
    
end

classA.m:

classdef classA < superclass
    
    %% PROPERTIES
    properties
        a;
    end
    
    %% METHODS
    methods
        % Constructor
        function obj = classA(a,y,z)
            x = a*z;
            obj@superclass(x,y);
            obj.a = a;
            obj.z = z;
        end
    end
    
end

classB.m:

classdef classB < superclass
    
    %% PROPERTIES
    properties
        b;
    end
    
    %% METHODS
    methods
        % Constructor
        function obj = classB(x,b,z)
            y = z+b;
            obj@superclass(x,y);
            obj.b = b;
            obj.z = z;
        end
    end
    
end

subclass.m:

classdef subclass < classA & classB
    
    %% METHODS
    methods
        % Constructor
        function obj = subclass(a,b,z)
            obj@classA(a,0,z);
            obj@classB(obj.x,b,z); % Why is this not allowed and how do I work around that
                                   % without redoing the calculations done in classes "classA" and "classB"?
        end
    end
    
end

This gives the following error message:

"A constructor call to superclass classB appears after the object is used, or after a return."

class , subclass , constructor , object-oriented , superclass , MATLAB , Programming , Classes , Def