title: NSDateFormatter giving one day back date
body: <p>Using NSDateFormatter to change format of date, it is but giving in return one day previous date of what is given to it. 
  Here is the code:</p>
  
  <pre><code>NSString *strDate = [self.mArrEventDate objectAtIndex:i];
  
  NSString *str = [[NSString alloc] init];
  str = [strDate stringByReplacingOccurrencesOfString:@"/" withString:@"-"];
  
  NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
  // ...using a date format corresponding to your date
  [dateFormatter setDateFormat:@"dd/MM/yyyy"];
  
  // Parse the string representation of the date
  NSDate *date = [dateFormatter dateFromString:strDate];
  
  NSDateFormatter *format1 = [[NSDateFormatter alloc]init];
  
  [format1 setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
  
  [format1 setDateFormat:@"yyyy-MM-dd"];
  
  NSString *sDate   = [format1 stringFromDate:date];
  </code></pre>