Re: passing by reference

[Paul Johnson]

I'm just going to restructure this sim so I don't have to pass by
reference, but it still niggles me that this does not work:

"Marcus G. Daniels" wrote:
> 
> >>>>> "PJ" == Paul Johnson <address@hidden> writes:
> 
> PJ> I saw after some study that I probably need to declare the method
> PJ> like so:  [..]
> 
> That latter one is right, but you still have to pass "&proposal",

That gives me:
ModelSwarm.m: In function `-[ModelSwarm buildActions]':
ModelSwarm.m:157: warning: passing arg 4 of `createActionTo:message:::'
from incompatible pointer type

>From ModelSwarm.m:
[modelActions createActionTo:  aSetter  message: M(makeProp:to:):
current: &proposal];
  
Setter.h has:
-(id) makeProp:  x to: (id *) p ;

-(id) makeProp:  x to: (id *) ptr {

    id p; 

      //here are steps *that work* and do create the new object p
      dimarray newpos;
      newpos[0]=0;
      newpos[1]=0;
      
      p = [PolicyPoint createBegin: [self getZone] ];
      [p setWorld: world];
      p= [p  createEnd];
      [p   setPos: newpos];
      [p   setPolicyColor: 2];    

         diff=[aNormalDist getDoubleSample];
         if (diff <= -2)  deltaTheta = -0.5* widthOfSearch;
         if (diff >= 2) deltaTheta = 0.5 * widthOfSearch;
         if (diff > -2 && diff < 2) deltaTheta =  (diff / 4.0) *
widthOfSearch; 

         angle= newangle + deltaTheta;
       distance= [uniformDblRand getDoubleWithMin: 0 withMax:
+longestStep];
  
       newpos[0]= [x getPolX] + distance*cos(angle*M_PI);
       newpos[1]= [x getPolY] + distance*sin(angle*M_PI); 
       [p setPos: newpos];  
       
       [p sayHi]; //confirms p exists, printfs values


     *ptr = p;  //tries to pass back by reference

    return self;
 }


-- 
Paul E. Johnson                       email: address@hidden
Dept. of Political Science            http://lark.cc.ukans.edu/~pauljohn
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66045                FAX: (785) 864-5700

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