(Newbie) Functions on vectors

Folks,

I want to make the following function more efficient, by vectorizing it:

getCriterionDecisionDate <- function (quarter , year)
{
 if (length(quarter) != length(year)) stop ("Quarter and year vectors
of unequal length!");
 ret <- character(0);

 for (i in 1:length(quarter)) {
   currQuarter <- quarter[i];
   currYear <- year[i];

   if ((currQuarter < 1) | (currQuarter > 4)) stop ("Invalid quarter!");
   if ((currYear < 1986) | (currYear > 2004)) stop ("Invalid year!");

   # If the criterion date is 1Q2004, then the reports were for periods
   # ending in Feb, March and April 2004 and the decision date is July 1, 2004.
   if (currQuarter == 1) {
     ret <- c(ret,paste("06/30/",currYear,sep=""));
   } else if (currQuarter == 2) {
     ret <- c(ret,paste("09/30/",currYear,sep=""));
   } else if (currQuarter == 3) {
     ret <- c(ret,paste("12/31/",currYear,sep=""));
   } else if (currQuarter == 4) {
     ret <- c(ret,paste("3/31/",currYear+1,sep=""));
   }
 }

 ret;
}


How can I make the 'if' statements work on vectors rather than using
one value at a time? (sorry, my copy of MASS is at home).

--
-- Vivek Satsangi
Student, Rochester, NY USA