Before:

// Determining whether a year is a leap year
bool isLeapYear( int year )
{
   if( year % 4 == 0 ) 
      if( year % 100 == 0 )
         if( year % 400 == 0 )
            return true;
         else
            return false;
      else
         return true;
   else
      return false;
}