Formating dates & numbers

Quick background I've been messing around with the ds1822 1-wire device and
a 4x20 LCD.  I now want to display the fahrenheit equivalent to the celsius
measurement along with the current date/time on a 4x20 LCD display.

tempF = tempC * 9 / 5 + 32;

With this I got values that were to large given the precision.

I thought I would fix this using some type of casting to round the numbers
to appropriate positions.

tempF = ((int)(tempC * 9 / 5 + 32)*100)/100.0;

This worked great for everything but the occasional 79.1000000000000001
which is far out of the range of the fairly consistent output now of XX.XX

I would appreciate any help with regards towards this interesting issue or
alternatives I might explore at truncating the number to my required
position.  Another option I explored was using a substr but I kept getting
errors on dereferencing a double so I thought this would be the best avenue.


Another issue I have had is with the lack of date/time extraction.  Using
the systronix demo tini I wrote a webserver that interfaced the RTC for fun
and found it very easy to work with.  However when using 1.12 and the 400 vs
390 I found that I cannot use anything worth wild to parse date/time
information.  The only way I have found to effectively work with the
date/time information I found in the archives.  They stated at the time to
try using the Gregorian object to parse date/time information.  So, I used
the following code:

Calendar calendar = new GregorianCalendar();
Date today = new Date();
calendar.setTime(today);
String timeLCD =
	calendar.get(Calendar.YEAR) + "-" +
	((calendar.get(Calendar.MONTH)<10)?"0":"") + calendar.get(Calendar.MONTH) +
"-" +
	((calendar.get(Calendar.DAY_OF_MONTH)<10)?"0":"") +
calendar.get(Calendar.DAY_OF_MONTH) + " " +
	calendar.get(Calendar.HOUR) + ":" +
	((calendar.get(Calendar.MINUTE)<10)?"0":"") + calendar.get(Calendar.MINUTE)
+ " " +
	((calendar.get(Calendar.AM_PM)==1)?"PM":"AM");


Notice a lack of seconds.  That is because it can take up to 5 seconds to
parse this string.  Is there a better way?
With the systronix demo I could use getHour getMinute etc... and the same
logic for adding zeros didn't cost more than a few ms maybe 10-50ms for a
total execution time of way less that 200ms vs. what I'm using now at
~5000ms.

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