ITEC 120 2010fall ibarland

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lab04b
if-else-if; helper functions
eBay fees

We will spend 5min discussing the syntax of if-else-if, and how you should always end with an else {…}, whether the overall if is initializing a variable or returning a value.

We will also go through the creation of one test case for totalEbayFee, and computeFVFee (discussing why the percentages are tiered the way they are).

Work on today's lab with a partner. You can write the following two-to-three methods in a class named, say, class EbayExpert.

Calculating eBay fees

If you sell an item on eBay, you are charged a fee. That total, overall fee is comprised of several parts:

• The insertion fee,
• the “final value fee” (which depends on how much you sold the item for),
and
• an optional extra fee if you want some fancy pictures in your listing: Gallery Plus fee.

Write a function totalEbayFee, so that eBay knows how much to charge each seller, when an auction finishes.

1. What two pieces of information does totalEbayFee need to know, so that it can determine the answer?
2. What Java data type is the best way to represent these pieces of info?
3. Write the signature for totalEbayFee, followed by the javadoc comments and some test cases.

4. Holy Smokes! Computing the overall fee has several parts; the part computing the final value fee is a sizeable task in itself!

   We will break this task into its own sub-function, which totalEbayFee will call as a helper function.

   Make test cases, signature, javadoc, and stub for computeFVFee.

5. Only after doing the above, write the body of the functions. Note that the test cases help you, to figure out how to compute the answer.

   Hint: You can write the body of totalEBayFee very easily once you can use computeFVFee.

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