try to manage a dynamic list of classinstances

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jeff wu
jeff wu 2012-3-24
hi its me again, i figured a lot out already thanks to your help, but there are still some misteries. i got this:
classdef node<handle
properties
x;
y;
bearing=0;
end % properties
methods
function obj = node(x,y)
obj.x=x;
obj.y=y;
end%functions
end%methods
end %class
and this:
classdef manlists
properties
nodelist={}
stablist={}
materiallist={}
formlist={}
end
methods
function f = manlists()
f.nodelist={node(1,2);node(2,3)};% as a try, and here works the node instance
f.stablist={};
f.materiallist={};
f.formlist={} ;
end
function h = grN(obj)
h = size(obj.nodelist,1);
end
function h = AddNode(a,b)
h.nodelist{end+1} =node(a,b)
end
end
end
but it doesnt work like i expect it to
in the command window it works
>> man = manlists;
>> man.nodelist{end+1}=node(1,2)
man =
manlists
Properties:
nodelist: {3x1 cell}
stablist: {}
materiallist: {}
formlist: {}
Methods
but inside the class i get this error:
>> man.AddNode(1,2)
??? Error using ==> AddNode
Too many input arguments.
i tried arround for several hours but i cant figure it out please help
thanks
  3 个评论
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Daniel Shub
Daniel Shub 2012-3-25
It is also strange to me that nodelist is a cell array instead of an array of class node.
per isakson
per isakson 2012-3-25
Why do you use cell arrays and not ordinary arrays?

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采纳的回答

Daniel Shub
Daniel Shub 2012-3-25
The call
man.AddNode(1,2)
is converted behind the scenes to
AddNode(man, 1, 2)
which has three arguments, but AddNode only takes 2 arguments. What I think you "want" is
function h = AddNode(h,a,b)
  1 个评论
jeff wu
jeff wu 2012-3-26
thanx a lot,
it works now in the way man = manlists; man = man.Addnode(1,2);
but is there a way to add a node without assigning man again;
actually i thought and what i wanted to do is that by calling man.Addnode(1,2) that one would automatically be added to the nodelist without deleting the previous.

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更多回答（1 个）

per isakson
per isakson 2012-3-25
Try
man = manlists;
man.nodelist(end+1) = node(1,2);
man = man.AddNode(1,2);
man.grN
with these two classes
classdef node < handle
properties
x;
y;
bearing=0;
end % properties
methods
function this = node(x,y)
this.x=x;
this.y=y;
end%functions
end%methods
end %class
classdef manlists
properties
nodelist = node.empty
end
methods
function this = manlists()
this.nodelist(end+1:end+2,1)=[ node(1,2); node(2,3)];
end
function sz = grN( this )
sz = size( this.nodelist, 1 );
end
function this = AddNode( this, a ,b )
this.nodelist(end+1) = node( a, b );
end
end
end
  2 个评论
Daniel Shub
Daniel Shub 2012-3-25
My guess is that at some point Wu is going to subclass node and therefore need to use a heterogeneous array. As it stands now, I like your way with standard arrays.
per isakson
per isakson 2012-3-26
@Daniel, Thanks! Yes, but this is just a little exercise.

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