exercism fetch racket say


Given a number from 0 to 999,999,999,999, spell out that number in English.

Step 1

Handle the basic case of 0 through 99.

If the input to the program is 22, then the output should be 'twenty-two'.

Your program should complain loudly if given a number outside the blessed range.

Some good test cases for this program are:


If you're on a Mac, shell out to Mac OS X's say program to talk out loud.

Step 2

Implement breaking a number up into chunks of thousands.

So 1234567890 should yield a list like 1, 234, 567, and 890, while the far simpler 1000 should yield just 1 and 0.

The program must also report any values that are out of range.

Step 3

Now handle inserting the appropriate scale word between those chunks.

So 1234567890 should yield '1 billion 234 million 567 thousand 890'

The program must also report any values that are out of range. It's fine to stop at "trillion".

Step 4

Put it all together to get nothing but plain English.

12345 should give twelve thousand three hundred forty-five.

The program must also report any values that are out of range.


Use and (correctly) when spelling out the number in English:

For installation and learning resources, refer to the exercism Racket page.

You can run the provided tests through DrRacket, or via the command line.

To run the test through DrRacket, simply open the test file and click the 'Run' button in the upper right.

To run the test from the command line, simply run the test from the exercise directory. For example, if the test suite is called hello-world-test.rkt, you can run the following command:

raco test hello-world-test.rkt

which will display the following:

raco test: (submod "hello-world-test.rkt" test)
2 success(es) 0 failure(s) 0 error(s) 2 test(s) run
2 tests passed


A variation on JavaRanch CattleDrive, exercise 4a http://www.javaranch.com/say.jsp

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