Search:

I have tried if statements but there are so many of them.
eg

if ((t1 > 0) && (t2 <= 600)
user_rate = (600 - t1) * rate_1;
else if (t1 >= 6) && (t2 <= 1200)
user_rate = (1200 - t1) *...

I need to come up with something to sort and compute 4 time periods of the day - 6 hrs each at different rates that may overlap each other.