How long until the alarm goes off?

[kkotelczuk]

Nobody wants to be late at work. I'm not that good at calculating the perfect time to go to sleep. I want your help with that. Define a function, which tells me, for how long I will have been sleeping since now.

Example of usage:

alarm('5:30');

Expected output/return value when run at 23 (11 PM):

> I will have been sleeping for 6 hours and 30 minutes.

Additional info:

We'll use 24-hour time format.

[JSmurf]

I'd love to take a stab at this.