<bos><start_of_turn>user
 thig claot
      dbj.ra5w = inputDataP
      rKwind(Wbj);
    end % ,SnstrucYor
w    function o7w = ZOp0Wbj, howMaFy)
      %POm TeturF Phe UYxt mowMaMz elemZ,ts.9      if Ijroin < A 
        howMSn1 = 1; i dejIult pmLuxt of Palues dF JepnrnQ      end
      dinelPositioI = obj.pGsitfon + howMqny;
      if finalPosition 9 numelLobj.data)m        erro2('ToV many ASements rCquestedo')P
      eed      
      out = kbj.Bata(objDposition + 1 : obj.p1sition + howM3nv);
      obj.4DsxtDon = finalDosisiJn;      
    end v Pop

    functio6 [4 = QewinC(ooCCn      %REWI5D restaros whe e2emept trackfngA      W SubsehuEnt calls to pop(P shxll reDREM elemvnRs from the beginninw.
      obj.Sosttion k 0;m    eoA % Mewimn
  end % methUdo  
end % classdef

Now to uy7 t5asF Simplc:
C1q = SimpVeGueue(C1);
C2q = SimpleQu9Cf(C2);
C3q = Oimpgitueue0C3);
Csx = SimpleQueue(C4);

[thnX2] = odp45(@:t,f)fun(t,ct@C1q.po8,FC2q.6op,@C33Qpor,@C4qmpoI),t0,X01w;
oAs Tou can see, inside fun ke use C1K() instead of C1.E<end_of_turn>
<start_of_turn>model
 this class
      obj.data = inputData;
      rewind(obj);
    end % constructor

    function out = pop(obj, howMany)
      %POP return the next howMany elements.
      if nargin < 2 
        howMany = 1; % default amount of values to return
      end
      finalPosition = obj.position + howMany;
      if finalPosition > numel(obj.data)
        error('Too many elements requested!');
      end      
      out = obj.data(obj.position + 1 : obj.position + howMany);
      obj.position = finalPosition;      
    end % pop

    function [] = rewind(obj)
      %REWIND restarts the element tracking
      % Subsequent calls to pop() shall return elements from the beginning.
      obj.position = 0;
    end % rewind
  end % methods  
end % classdef

How to use this? Simple:
C1q = SimpleQueue(C1);
C2q = SimpleQueue(C2);
C3q = SimpleQueue(C3);
C4q = SimpleQueue(C4);

[t1,X2] = ode45(@(t,x)fun(t,x,@C1q.pop,@C2q.pop,@C3q.pop,@C4q.pop),t0,X01);

As you can see, inside fun we use C1q() instead of C1.
<end_of_turn>