add variable in for loop

Hi,

I'm learning to write some basic functions in R. For some data I have I'd
like to be able to add a variable to itself after each iteration in a for
loop to obtain a grandtotal for that variable so I can calculate a mean.

test<-function(data){
	for (i in 1:80){

meanrotation<-(abs(data[i,3]-data[i,2])+abs(data[i,4]-data[i,2])+abs(data[i,5]-data[i,2])+abs(data[i,6]-data[i,2]))/4
	cat(i,meanrotation,"\n")
	#total+=meanrotation
	}
	#print (total/80)
	}

In perl there's an assignment operator variable+=variable2. Is there
anything like this in R to do as illustrated in the code above.

thanks a lot,

Paul

Edit - I guess the other way to do this which I just realised is to assign
the output of the function to a vector and then do a summary(), but I don't
know how to do this either - help is appreciated