achinn / pretty-prices

Pretty Prices

Problem

Converting between currencies can result in funny-looking results.

Suppose the exchange rate is 1.34 CA$ / US$. A product that costs a familiar US$ 9.99, will cost CA$ 13.39.

US$  9.99
 *   1.34
 -------
CA$ 13.39

Shoppers aren't always used to prices ending in 0.39!

How can we round prices to look "normal"?

Goal

Extend PriceConverter.java to return prices rounded...

1. up to the nearest quarter (ending in .00, .25, .50, .75)
   • e.g. 9.99 * 1.34 = 13.39 --> 13.50
2. up or down to the nearest quarter. (Have the user specify.)
   • e.g. rounding down 9.99 * 1.34 = 13.39 --> 13.25
3. up to the nearest user-provided multiple (e.g., nearest 0.10, 0,05, 0.20, ...)
   • e.g. rounding up to nearest 0.20 9.99 * 1.34 = 13.39 --> 13.40
4. up to end in .99 cents (e.g. 13.39 -> 13.99)
   • e.g. 9.99 * 1.34 = 13.39 --> 13.99
   • Note: this is not the same as rounding up to a multiple of 0.99 (why?)
5. up to end in any amount
   • e.g. round to end in 0.13 9.99 * 1.34 = 13.39 --> 14.13

If you've done all the above, PriceConverter.java should be able to...

• round either up or down
• to a multiple of X
• or to an ending of X

---

Useful commands

• Test: mvn test
• Build: mvn compile
• Run: mvn exec:java -Dexec.mainClass="com.shopify.prettyprices.Main"

Alternately, without Maven magic, from src/main/java directory:

• build: javac com/shopify/prettyprices/*.java
• run: java com.shopify.prettyprices.Main