iPHONE SDK - Subtracting a time given another time
<p>having trouble with this. i need to come up with a logic code.</p>

<p>How do i, given 2 set of times. subtract one from the other and change it all to seconds.</p>

<p>Lets say i have '12:00:00' and '15:00:00'
Now i want to subtract 12:00:00 from 15:00:00 so the result will be 03:00:00. Then change it all to seconds so that will be 10800 seconds</p>

<p>i already have two sets of time in an NSString after being Formatted with a NSDateFormatter</p>
