Class association has error

Question

shawin 2016-11-23

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/313616-class-association-has-error

编辑： Adam 2016-11-23

I have the code bellow:

Course.m

   classdef Course < handle
    properties   
        courseName
        stdent
    end
    properties ( Access= private) 
        lastIDX=1    
    end
    methods 
    function obj= Course(courseName, capacity)  
        obj.courseName=  courseName
        obj.stdent= cell(capacity,1)
    end 
    function addStudent(obj,stdent) 
           if obj.lastIDX > numel(obj.stdent)
            fprintf(2,'sorry class is full`an');
          return
           end 
       obj.stdent(obj.lastIDX)=stdent;
       obj.lastIDX= obj.lastIDX +1;
    end 
    function printClass(obj)
        fprintf('course name = %s\n ', obj.courseName)
        fprintf('Enroled =%d , capacity =%d\n', obj.lastIDX-1, length(obj.stdent));
        for i =1:obj.lastIDX-1 
            fprintf('ID =%d, name = %s\n', i, obj.stdent{i}.name);
        end    
    end
     end 
   end 
   StudentTest1.m
   classdef studentTest1 < handle
    properties 
        name
    end
   methods 
    function obj=studentTest1(name)
       if nargin  > 0
         obj.name=name;    
       end 
    end
    function delete(obj)
     fprintf('--Student Destructor: %s\n',obj.name); 
      end  
     end
   end

I call the objects :

   c = Course('AAA',3);
    for i = 1 :4 
    name= fprintf('amro%d',i);
    fprintf('Adding  student :%s\n', name)
    c.addStudent(name);
   end 
   c.printClass()
   clear c
but receiving error :
Error using Course
The specified superclass 'handle' contains a parse error, cannot be found on MATLAB's search path or is shadowed by another file with the same name.

Error in TestStudentCourse (line 6) c = Course('AI',3);

any help, please

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Adam 2016-11-23

编辑：Adam 2016-11-23

Please don't edit away the original question to turn it into a new one when fixing the first problem just leads to another one, it is very confusing and doesn't help any future people coming to the question and looking at the answer provided which no longer makes much sense, relative to the question.

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Answer 1

Guillaume 2016-11-23

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https://ww2.mathworks.cn/matlabcentral/answers/313616-class-association-has-error#answer_244414

在 MATLAB Online 中打开

Well, learn to read error messages. It's telling you that the superclass handel cannot be found. That's because you misspelled it, it should be handle.

classdef Course < handle

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Guillaume 2016-11-23

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Learn to debug your program. The simplest way is to issue

dbstop if error.

then run the code. It will break into the debugger at the line where the error occurs. Look at what is in obj.stdent{i}. Most likely it's not a studentTest object. What is it?

Adam 2016-11-23

编辑：Adam 2016-11-23

在 MATLAB Online 中打开

I make very heavy use of

doc validateattributes

for the input arguments of all my public functions of classes to ensure that when something gets passed into the function I know exactly what it is (for ease of debugging purposes, but also for documentation) and if I pass the wrong thing in it will give an error with an error message that tells me exactly this rather than sliding down through the code to some potentially obscure error when it actually tries to use the object.

It obviously adds a small amount to your development time and the runtime, but neither is significant to me compared to the value it gives me for debugging and coming back to a class 6 months down the line when I can't remember if theat 2nd input argument was supposed to be a string or a scalar or some object or other of my own class, etc.

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