A telecom company wants to implement a simple system for call billing.
In their call plans there are different types of tariff:
- regular calls at 0.05 pence per minute
- late night calls (for example from 10pm to 4am) at 0.02 pence per minute
- weekend calls at 0.01 pence per minute
There are two kinds of clients that the company manages:
- New clients who have been given a discount on their regular calls (regular calls pay the same rate as late night calls)
- Existing clients who pay the standard rates mentioned above
In addition the company uses the following rule to charge for local & international calls:
- International calls double the rate per minute
The company is interested in implementing a simple billing system to calculate the total charge to a client given their call history.