Brief

Clean up user-entered phone numbers so that they can be sent SMS messages.

The North American Numbering Plan (NANP) is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda. All NANP-countries share the same international country code: 1.

NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as area code, followed by a seven-digit local number. The first three digits of the local number represent the exchange code, followed by the unique four-digit number which is the subscriber number.

The format is usually represented as

(NXX)-NXX-XXXX

where N is any digit from 2 through 9 and X is any digit from 0 through 9.

Your task is to clean up differently formated telephone numbers by removing punctuation and the country code (1) if present.

For example, the inputs

• +1 (613)-995-0253
• 613-995-0253
• 1 613 995 0253
• 613.995.0253

should all produce the output below from a Number() function.

6139950253

Additionally, a Format() function should produce the output

(613) 995-0253

and an AreaCode() function should output

613

Note: As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.

Coding the solution

Look for a stub file having the name phone_number.go and place your solution code in that file.

Running the tests

To run the tests run the command go test from within the exercise directory.

If the test suite contains benchmarks, you can run these with the --bench and --benchmem flags:

go test -v --bench . --benchmem

Keep in mind that each reviewer will run benchmarks on a different machine, with different specs, so the results from these benchmark tests may vary.

Evaluation Criteria

• Go best practices
• Show us your work through your commit history
• Completeness: did you complete the features? Are all the tests running?
• Correctness: does the functionality act in sensible, thought-out ways?
• Maintainability: is it written in a clean, maintainable way?

CodeSubmit

Please organize, design, and document your code as if it were going into production - then push your changes to the master branch. After you have pushed your code, you may submit the assignment on the assignment page.

All the best and happy coding,

The Seagate Team