Problem with object oriented progamming - codepedent variables

Question

Teodor 2014-4-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/125680-problem-with-object-oriented-progamming-codepedent-variables

回答： Teodor 2014-4-15

Hello guys, I've got a problem with a class of the object that I want to create. I want it to work in that way: Once I change the parameter 'A', I want second parameter 'B' to change automatically, and once I change the second parameter 'B' I want the first parameter 'A' change adequatly:

   classdef ModelBrick
   properties   
     A=1
     B=1
   end
   methods
        function a= set.A(obj)        
                obj.A=a*obj.B;
        end
        function b= set.B(obj)        
                obj.B=obj.A/b;
        end
    end
end

Obviously it doesn't work. It enters into infinit loop. Do you have any idea how to deal with this problem? Thank you in advance.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Teodor 2014-4-15

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/125680-problem-with-object-oriented-progamming-codepedent-variables#answer_133412

在 MATLAB Online 中打开

Thanks a lot Matt for your time. I found the answer thank to you.

classdef ModelBrick   
   properties   
            B=1
            C=20
   end   
  properties(Dependent = true)
      A=1
  end % end of dependent properties
     methods    
          function obj= set.A(obj,a)     
                obj.B=a/obj.C
          end    
          function a= get.A(obj)        
              a=obj.B*obj.C;
          end    
    end

end

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Matt J 2014-4-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/125680-problem-with-object-oriented-progamming-codepedent-variables#answer_133310

在 MATLAB Online 中打开

No, the code you've shown won't enter an infinite loop. It will generate an error because the parameter "a" in

obj.A=a*obj.B;

is never passed to set.A() as an input argument and similarly for the parameter "b". Also, set methods need to return an obj of the class instead of numeric scalars like a and b.

However, the solution to your problem is probably to make either A or B a Dependent Property.

2 个评论
显示无隐藏无

Matt J 2014-4-14

在 MATLAB Online 中打开

Teodor Commented:

Sorry, you are right, but if I put that way:

 classdef ModelBrick
   properties   
     A=1
     B=1
   end
   methods
        function obj= set.A(obj,a)     
                obj.A=a*obj.B;
        end
        function obj= set.B(obj,b)        
                obj.B=obj.A/b;
        end
    end
end

It doesn't work neither.

Matt J 2014-4-14

Works fine for me, i.e., I get no error messages. The Code Analyzer does warn you not to refer to multiple properties in the set() methods and you should take that seriously. That's why I referred you earlier to the documentation on Dependent Properties

http://www.mathworks.com/help/matlab/matlab_oop/example--representing-structured-data.html#f2-85430

请先登录，再进行评论。