timecard calculator problem...

[skeptik]

Okay... pretty simple, but i just wanted verification, does this look right?

I'll be implementing this into a command-line based app, otherwise I'd use some spreadsheet or something.

Data

   x	in	09:25
	out	13:14

   y	in	13:45
	out	18:13

Formula

   hours(x,y) = ((in[hour] * 60 + in[minute]) - (out[hour] * 60 + out[minute])) / 60

Example
     
   x(3.42) = ((9 * 60 + 25) - (13 * 60 + 14)) / 60
   y(4.47) = ((13 * 60 + 45) - (18 * 60 + 13)) / 60
   z(7.89) = x + y

[Dave_Sinkula]

It seems to me the duration should be

{hours} = {out} - {in}

rather than

{hours} = {in} - {out}

Do you need to compensate for crossing a day boundary (that is, when you finish "before" you start)?