time logic issue

Question

hi, i am working in vb.net 2003(windows application) i have three slots ie total working hours=24 works starts from slot1: 8am to 5pm slot2: 5pm to 12am slot3: 12am to 8am say for example if i am working morning 6am to 3 pm(in the same day) i wan to check in which time slots i worked.(in this example i worked 2 hours in slot3 and 7 hours in slot1). so like this i want to find the slots i workend and how many hours i worked in the slots if we give the time can anyone help me to do with example coding please