Awk diff of squares

awk/README.md

@@ -34,3 +34,4 @@
 - [space-age](./space-age/README.md)
 - [all-your-base](./all-your-base/README.md)
 - [high-scores](./high-scores/README.md)
+- [difference-of-squares](./difference-of-squares/README.md)

awk/difference-of-squares/.exercism/config.json

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+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "difference-of-squares.awk"
+    ],
+    "test": [
+      "test-difference-of-squares.bats"
+    ],
+    "example": [
+      ".meta/example.awk"
+    ]
+  },
+  "blurb": "Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.",
+  "source": "Problem 6 at Project Euler",
+  "source_url": "https://projecteuler.net/problem=6"
+}

awk/difference-of-squares/.exercism/metadata.json

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+{"track":"awk","exercise":"difference-of-squares","id":"488e8fafe396433c9d3455749663cac9","url":"https://exercism.org/tracks/awk/exercises/difference-of-squares","handle":"vpayno","is_requester":true,"auto_approve":false}

awk/difference-of-squares/HELP.md

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+# Help
+
+## Running the tests
+
+Each exercise contains a test file.
+Run the tests using the `bats` program.
+```bash
+bats test-hello-world.bats
+```
+
+`bats` will need to be installed.
+See the [Testing on the Bash track][bash] page for instructions to install `bats` for your system.
+
+### bats is implemented in bash
+
+The bats file is a bash script, with some special functions recognized by the `bats` command.
+You'll see some tests that look like
+```sh
+gawk -f some-exercise.awk <<< "some,input,here"
+```
+That `<<<` syntax is a bash [Here String][here-string].
+It sends the string on the right-hand side into the standard input of the program on the left-hand side.
+It is ([approximately][so]) the same as
+```sh
+echo "some,input,here" | gawk -f some-exercise.awk
+```
+
+## Help for assert functions
+
+The tests use functions from the [bats-assert][bats-assert] library.
+Help for the various `assert*` functions can be found there.
+
+## Skipped tests
+
+Solving an exercise means making all its tests pass.
+By default, only one test (the first one) is executed when you run the tests.
+This is intentional, as it allows you to focus on just making that one test pass.
+Once it passes, you can enable the next test by commenting out or removing the
+
+    [[ $BATS_RUN_SKIPPED == true ]] || skip
+
+annotations prepending other tests.
+
+## Overriding skips
+
+To run all tests, including the ones with `skip` annotations, you can run:
+```bash
+BATS_RUN_SKIPPED=true bats test-some-exercise.bats
+```
+
+It can be convenient to use a wrapper function to save on typing: in `bash` you can do:
+```bash
+bats() {
+    BATS_RUN_SKIPPED=true command bats *.bats
+}
+```
+Then run tests with just:
+```bash
+bats
+```
+
+[bash]: https://exercism.org/docs/tracks/bash/tests
+[bats-assert]: https://github.com/bats-core/bats-assert
+[here-string]: https://www.gnu.org/software/bash/manual/bash.html#Here-Strings
+[so]: https://unix.stackexchange.com/a/80372/4667
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit difference-of-squares.awk` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [AWK track's documentation](https://exercism.org/docs/tracks/awk)
+- The [AWK track's programming category on the forum](https://forum.exercism.org/c/programming/awk)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+Places to look for help for AWK questions:
+
+* [Stack Overflow `awk` tag][so].
+* check the Resources section of the [Stack Overflow `awk` tag into page][so-info].
+* raise an issue at the [exercism/awk][github] Github repository.
+* IRC: `irc://irc.liberachat.net/#awk`, `irc://irc.liberachat.net/#exercism`
+    * see [Libera.chat][libera] if you're unfamiliar with IRC.
+
+
+[so]: https://stackoverflow.com/tags/awk
+[so-info]: https://stackoverflow.com/tags/awk/info
+[github]: https://github.com/exercism/awk
+[libera]: https://libera.chat

awk/difference-of-squares/README.md

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+# Difference of Squares
+
+Welcome to Difference of Squares on Exercism's AWK Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
+
+The square of the sum of the first ten natural numbers is
+(1 + 2 + ... + 10)² = 55² = 3025.
+
+The sum of the squares of the first ten natural numbers is
+1² + 2² + ... + 10² = 385.
+
+Hence the difference between the square of the sum of the first ten natural numbers and the sum of the squares of the first ten natural numbers is 3025 - 385 = 2640.
+
+You are not expected to discover an efficient solution to this yourself from first principles; research is allowed, indeed, encouraged.
+Finding the best algorithm for the problem is a key skill in software engineering.
+
+## Source
+
+### Created by
+
+- @glennj
+
+### Based on
+
+Problem 6 at Project Euler - https://projecteuler.net/problem=6
+
+### My Solution
+
+- [my solution](./difference-of-squares.awk)
+- [awkunit tests](./difference-of-squares_test.awk)
+- [test cases](./test-cases.awk)
+- [run-tests](./run-tests-awk.txt)

awk/difference-of-squares/awkunit.awk

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+../.lib/awkunit.awk