Help: Pulling integers out of a string, then making a comparison

EDIT:

I think I can explain more about what I am talking about:

My time string displays as HOURS:MINUTES:SECONDS. Example: 22:04:41

My alarmhour and alarmminute are 2 integers set by the user using potentiometers and stored as a variable. For example.

alarmhour = 5;
alarminute = 30;

My question lies, how can I convert my alarm time to a string, appending a zero of course to the end for seconds. that way I can use an IF statement to see if my alarm string matches my time string.