98 lines
3 KiB
Markdown
98 lines
3 KiB
Markdown
# Say
|
|
|
|
Write a program that will take a number from 0 to 999,999,999,999 and 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:
|
|
|
|
- 0
|
|
- 14
|
|
- 50
|
|
- 98
|
|
- -1
|
|
- 100
|
|
|
|
### Extension
|
|
|
|
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.
|
|
|
|
### Extensions
|
|
|
|
Use _and_ (correctly) when spelling out the number in English:
|
|
|
|
- 14 becomes "fourteen".
|
|
- 100 becomes "one hundred".
|
|
- 120 becomes "one hundred and twenty".
|
|
- 1002 becomes "one thousand and two".
|
|
- 1323 becomes "one thousand three hundred and twenty-three".
|
|
|
|
## Getting Started
|
|
|
|
Make sure you have read [the C++ page](http://exercism.io/languages/cpp) on
|
|
exercism.io. This covers the basic information on setting up the development
|
|
environment expected by the exercises.
|
|
|
|
## Passing the Tests
|
|
|
|
Get the first test compiling, linking and passing by following the [three
|
|
rules of test-driven development](http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd).
|
|
Create just enough structure by declaring namespaces, functions, classes,
|
|
etc., to satisfy any compiler errors and get the test to fail. Then write
|
|
just enough code to get the test to pass. Once you've done that,
|
|
uncomment the next test by moving the following line past the next test.
|
|
|
|
```C++
|
|
#if defined(EXERCISM_RUN_ALL_TESTS)
|
|
```
|
|
|
|
This may result in compile errors as new constructs may be invoked that
|
|
you haven't yet declared or defined. Again, fix the compile errors minimally
|
|
to get a failing test, then change the code minimally to pass the test,
|
|
refactor your implementation for readability and expressiveness and then
|
|
go on to the next test.
|
|
|
|
Try to use standard C++11 facilities in preference to writing your own
|
|
low-level algorithms or facilities by hand. [CppReference](http://en.cppreference.com/)
|
|
is a wiki reference to the C++ language and standard library. If you
|
|
are new to C++, but have programmed in C, beware of
|
|
[C traps and pitfalls](http://www.slideshare.net/LegalizeAdulthood/c-traps-and-pitfalls-for-c-programmers).
|
|
|
|
## Source
|
|
|
|
A variation on JavaRanch CattleDrive, exercise 4a [view source](http://www.javaranch.com/say.jsp)
|