71 lines
2.1 KiB
Markdown
71 lines
2.1 KiB
Markdown
# Leap
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Given a year, report if it is a leap year.
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The tricky thing here is that a leap year in the Gregorian calendar occurs:
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```text
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on every year that is evenly divisible by 4
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except every year that is evenly divisible by 100
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unless the year is also evenly divisible by 400
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```
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For example, 1997 is not a leap year, but 1996 is. 1900 is not a leap
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year, but 2000 is.
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## Notes
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Though our exercise adopts some very simple rules, there is more to
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learn!
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For a delightful, four minute explanation of the whole leap year
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phenomenon, go watch [this youtube video][video].
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[video]: http://www.youtube.com/watch?v=xX96xng7sAE
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Run the tests with:
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```bash
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bats leap_test.sh
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```
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After the first test(s) pass, continue by commenting out or removing the
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`[[ $BATS_RUN_SKIPPED == true ]] || skip`
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annotations prepending other tests.
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To run all tests, including the ones with `skip` annotations, run:
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```bash
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BATS_RUN_SKIPPED=true bats leap_test.sh
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```
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## Source
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JavaRanch Cattle Drive, exercise 3 [http://www.javaranch.com/leap.jsp](http://www.javaranch.com/leap.jsp)
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## External utilities
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`Bash` is a language to write "scripts" -- programs that can call
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external tools, such as
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[`sed`](https://www.gnu.org/software/sed/),
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[`awk`](https://www.gnu.org/software/gawk/),
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[`date`](https://www.gnu.org/software/coreutils/manual/html_node/date-invocation.html)
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and even programs written in other programming languages,
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like [`Python`](https://www.python.org/).
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This track does not restrict the usage of these utilities, and as long
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as your solution is portable between systems and does not require
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installation of third party applications, feel free to use them to solve
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the exercise.
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For an extra challenge, if you would like to have a better understanding
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of the language, try to re-implement the solution in pure `Bash`,
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without using any external tools. Note that there are some types of
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problems that bash cannot solve, such as performing floating point
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arithmetic and manipulating dates: for those, you must call out to an
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external tool.
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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
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have completed the exercise.
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