13.2 [30] 

The price schedule provided to KFC for cases of fried chicken buckets offers discounts depending on the number of cases of buckets ordered. The schedule is shown in the table below, which is reproduced from Problem 11.3.

Quantity Price 1-399 $21.00 400-1199 $18.00 1200 or more $17.40

Write a macro called BucketPrice which accepts a single argument that represents the quantity ordered, and returns a value equal to the price of a case of buckets. Your macro should assume that its argument is any number greater than or equal to 1. If it receives an argument that isn't an integer, it should truncate the fractional part of the argument and return a result as if it had received an integer argument. Demonstrate your macro for these arguments: 276.00, 400.00, 431.27, 1899.20.

13.3 [40] 

In the course of modeling operations at KFC, you find that you buy several products with three-step "staircase" price schedules as in Problem 13.2. You could write a separate function macro for each one, but that approach is wasteful and creates duplicated code. So you decide instead to write a single macro that is invoked by each specialized macro. This is more reliable because it concentrates all the "thinking" in a single place.

(a) [20] 

The macro is called Staircase3, and does all the hard work for all three-step staircase pricing. It returns a single floating-point number — the price for the quantity specified. It accepts six arguments, ordered as follows:

quantity

The quantity whose unit price is to be determined by Staircase3. If it receives a value that isn't an integer, it should truncate the fractional part of the argument and return a result as if it had received an integer argument.

price0

The undiscounted price. In the chicken buckets example, this argument would have the value $21.00. A floating-point number.

thresh1

The minimum number of units required for the first discount level. In the chicken buckets example, this argument would have the value 400. A large integer.

price1

The first level of discounted price. In the chicken buckets example, this argument would have the value $18.00. A floating-point number.

thresh2

The minimum number of units required for the second discount level. In the chicken buckets example, this argument would have the value 1200. A large integer.

price2

The second level of discounted price. In the chicken buckets example, this argument would have the value $17.40. A floating-point number.

Write the macro Staircase3, and demonstrate that it gives correct chicken-bucket prices for the chicken-bucket price schedule and these order quantities: 276.00, 400.00, 431.27, 1899.20.

(b) [20] 

Rewrite the macro BucketPrice, calling it BucketPrice3, so that it behaves exactly like BucketPrice, but computes its results by invoking Staircase3 internally. Price3 takes a single argument, and produces results identical to Price. Demonstrate its use with the four values 276.00, 400.00, 431.27, 1899.20.