51 lines
1.8 KiB
Markdown
51 lines
1.8 KiB
Markdown
# Armstrong Numbers
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An [Armstrong number](https://en.wikipedia.org/wiki/Narcissistic_number) is a number that is the sum of its own digits each raised to the power of the number of digits.
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For example:
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- 9 is an Armstrong number, because `9 = 9^1 = 9`
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- 10 is *not* an Armstrong number, because `10 != 1^2 + 0^2 = 1`
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- 153 is an Armstrong number, because: `153 = 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153`
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- 154 is *not* an Armstrong number, because: `154 != 1^3 + 5^3 + 4^3 = 1 + 125 + 64 = 190`
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Write some code to determine whether a number is an Armstrong number.
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## Getting Started
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Make sure you have read the "Guides" section of the
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[C track][c-track] on the Exercism site. This covers
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the basic information on setting up the development environment expected
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by the exercises.
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## Passing the Tests
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Get the first test compiling, linking and passing by following the [three
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rules of test-driven development][3-tdd-rules].
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The included makefile can be used to create and run the tests using the `test`
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task.
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make test
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Create just the functions you need to satisfy any compiler errors and get the
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test to fail. Then write just enough code to get the test to pass. Once you've
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done that, move onto the next test.
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As you progress through the tests, take the time to refactor your
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implementation for readability and expressiveness and then go on to the next
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test.
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Try to use standard C99 facilities in preference to writing your own
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low-level algorithms or facilities by hand.
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## Source
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Wikipedia [https://en.wikipedia.org/wiki/Narcissistic_number](https://en.wikipedia.org/wiki/Narcissistic_number)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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[c-track]: https://exercism.io/my/tracks/c
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[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd
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