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93 lines
3.3 KiB
93 lines
3.3 KiB
4 years ago
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# 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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## Rust Installation
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Refer to the [exercism help page][help-page] for Rust installation and learning
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resources.
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## Writing the Code
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Execute the tests with:
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```bash
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$ cargo test
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```
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All but the first test have been ignored. After you get the first test to
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pass, open the tests source file which is located in the `tests` directory
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and remove the `#[ignore]` flag from the next test and get the tests to pass
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again. Each separate test is a function with `#[test]` flag above it.
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Continue, until you pass every test.
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If you wish to run all ignored tests without editing the tests source file, use:
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```bash
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$ cargo test -- --ignored
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```
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To run a specific test, for example `some_test`, you can use:
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```bash
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$ cargo test some_test
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```
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If the specific test is ignored use:
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```bash
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$ cargo test some_test -- --ignored
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```
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To learn more about Rust tests refer to the [online test documentation][rust-tests]
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Make sure to read the [Modules][modules] chapter if you
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haven't already, it will help you with organizing your files.
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## Further improvements
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After you have solved the exercise, please consider using the additional utilities, described in the [installation guide](https://exercism.io/tracks/rust/installation), to further refine your final solution.
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To format your solution, inside the solution directory use
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```bash
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cargo fmt
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```
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To see, if your solution contains some common ineffective use cases, inside the solution directory use
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```bash
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cargo clippy --all-targets
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```
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## Submitting the solution
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Generally you should submit all files in which you implemented your solution (`src/lib.rs` in most cases). If you are using any external crates, please consider submitting the `Cargo.toml` file. This will make the review process faster and clearer.
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## Feedback, Issues, Pull Requests
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The [exercism/rust](https://github.com/exercism/rust) repository on GitHub is the home for all of the Rust exercises. If you have feedback about an exercise, or want to help implement new exercises, head over there and create an issue. Members of the rust track team are happy to help!
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If you want to know more about Exercism, take a look at the [contribution guide](https://github.com/exercism/docs/blob/master/contributing-to-language-tracks/README.md).
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[help-page]: https://exercism.io/tracks/rust/learning
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[modules]: https://doc.rust-lang.org/book/ch07-02-defining-modules-to-control-scope-and-privacy.html
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[cargo]: https://doc.rust-lang.org/book/ch14-00-more-about-cargo.html
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[rust-tests]: https://doc.rust-lang.org/book/ch11-02-running-tests.html
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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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