void cb(){	

	//make some datasets attached to columns of active sheet as you described.
	Worksheet wks=Project.ActiveLayer();
	Dataset dsIn, ds1, ds0;	
	
	dsIn.Attach(wks,0);
	ds1.Attach(wks, 1);
	ds0.Attach(wks, 2);

	ds0.SetSize(dsIn.GetSize());
	ds1.SetSize(dsIn.GetSize());
	ds0=NANUM;
	ds1=NANUM;
	
	//declare some counters.
	int iOneCount=0;  //number of 'periods of 1s' observed.
	int iZeroCount=0; //number of 'periods of 0s' observed.
	int iSame=1;      //number of observations in current period.
	
	for (int j=1;j<dsIn.GetSize();j++){  //progress through entire input column.
		if (dsIn[j]!=dsIn[j-1]){  //if current value does not equal previous, change has occured.
		
			if (dsIn[j-1]==1){ //change was from 1 to 0 so output to 1s counter.
				ds1[iOneCount++]=iSame;
			}
			else{			   //change was from 0 to 1 so output to 0s coutner.
				ds0[iZeroCount++]=iSame;
			}			
			iSame=1;  //output of period complete, so reset streak counter.
		}
		else	iSame++;	//no change occured, so increment streak counter.	
	}
	
	//finally, take care of the last period.
	if (dsIn[j-1]==1){
		ds1[iOneCount++]=iSame; 
	}
	else{
		ds0[iZeroCount++]=iSame;
	}
	ds0.SetSize(iZeroCount);
	ds1.SetSize(iOneCount);	
	
}