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Armstrong Numbers
An Armstrong number is a number that is the sum of its own digits each raised to the power of the number of digits.
For example:
- 9 is an Armstrong number, because
9 = 9^1 = 9 - 10 is not an Armstrong number, because
10 != 1^2 + 0^2 = 1 - 153 is an Armstrong number, because:
153 = 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153 - 154 is not an Armstrong number, because:
154 != 1^3 + 5^3 + 4^3 = 1 + 125 + 64 = 190
Write some code to determine whether a number is an Armstrong number.
Rust Installation
Refer to the exercism help page for Rust installation and learning resources.
Writing the Code
Execute the tests with:
$ cargo test
All but the first test have been ignored. After you get the first test to
pass, open the tests source file which is located in the tests directory
and remove the #[ignore] flag from the next test and get the tests to pass
again. Each separate test is a function with #[test] flag above it.
Continue, until you pass every test.
If you wish to run all ignored tests without editing the tests source file, use:
$ cargo test -- --ignored
To run a specific test, for example some_test, you can use:
$ cargo test some_test
If the specific test is ignored use:
$ cargo test some_test -- --ignored
To learn more about Rust tests refer to the online test documentation
Make sure to read the Modules chapter if you haven't already, it will help you with organizing your files.
Further improvements
After you have solved the exercise, please consider using the additional utilities, described in the installation guide, to further refine your final solution.
To format your solution, inside the solution directory use
cargo fmt
To see, if your solution contains some common ineffective use cases, inside the solution directory use
cargo clippy --all-targets
Submitting the solution
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.
Feedback, Issues, Pull Requests
The 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!
If you want to know more about Exercism, take a look at the contribution guide.
Source
Wikipedia https://en.wikipedia.org/wiki/Narcissistic_number
Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.