commit 506c52e353baca3dc31cc6742dd3caada8b5363c Author: Jim Infield Date: Wed Mar 20 20:20:20 2019 -0600 initial commit diff --git a/.exercism/metadata.json b/.exercism/metadata.json new file mode 100644 index 0000000..3d2cd69 --- /dev/null +++ b/.exercism/metadata.json @@ -0,0 +1 @@ +{"track":"go","exercise":"leap","id":"395651d5e2594caca279b138a2b7701b","url":"https://exercism.io/my/solutions/395651d5e2594caca279b138a2b7701b","handle":"jinfield","is_requester":true,"auto_approve":false} \ No newline at end of file diff --git a/README.md b/README.md new file mode 100644 index 0000000..cce7ebf --- /dev/null +++ b/README.md @@ -0,0 +1,67 @@ +# Leap + +Given a year, report if it is a leap year. + +The tricky thing here is that a leap year in the Gregorian calendar occurs: + +```text +on every year that is evenly divisible by 4 + except every year that is evenly divisible by 100 + unless the year is also evenly divisible by 400 +``` + +For example, 1997 is not a leap year, but 1996 is. 1900 is not a leap +year, but 2000 is. + +If your language provides a method in the standard library that does +this look-up, pretend it doesn't exist and implement it yourself. + +## Notes + +Though our exercise adopts some very simple rules, there is more to +learn! + +For a delightful, four minute explanation of the whole leap year +phenomenon, go watch [this youtube video][video]. + +[video]: http://www.youtube.com/watch?v=xX96xng7sAE + +You will see a `cases_test.go` file in this exercise. This holds the test +cases used in the `leap_test.go`. You can mostly ignore this file. + +However, if you are interested... we sometimes generate the test data from a +[cross language repository][problem-specifications-leap]. In that repo +exercises may have a [.json file][problem-specifications-leap-json] that +contains common test data. Some of our local exercises have an +[intermediary program][local-leap-gen] that takes the problem specification +JSON and turns in into Go structs that are fed into the `_test.go` +file. The Go specific transformation of that data lives in the `cases_test.go` file. + +[problem-specifications-leap]: https://github.com/exercism/problem-specifications/tree/master/exercises/leap +[problem-specifications-leap-json]: https://github.com/exercism/problem-specifications/blob/master/exercises/leap/canonical-data.json +[local-leap-gen]: https://github.com/exercism/go/blob/master/exercises/leap/.meta/gen.go + + +## Running the tests + +To run the tests run the command `go test` from within the exercise directory. + +If the test suite contains benchmarks, you can run these with the `--bench` and `--benchmem` +flags: + + go test -v --bench . --benchmem + +Keep in mind that each reviewer will run benchmarks on a different machine, with +different specs, so the results from these benchmark tests may vary. + +## Further information + +For more detailed information about the Go track, including how to get help if +you're having trouble, please visit the exercism.io [Go language page](http://exercism.io/languages/go/resources). + +## Source + +JavaRanch Cattle Drive, exercise 3 [http://www.javaranch.com/leap.jsp](http://www.javaranch.com/leap.jsp) + +## Submitting Incomplete Solutions +It's possible to submit an incomplete solution so you can see how others have completed the exercise. diff --git a/cases_test.go b/cases_test.go new file mode 100644 index 0000000..d59218a --- /dev/null +++ b/cases_test.go @@ -0,0 +1,17 @@ +package leap + +// Source: exercism/problem-specifications +// Commit: 3134d31 leap 1.4.0: negative test: year divisible by 200, not by 400 +// Problem Specifications Version: 1.4.0 + +var testCases = []struct { + year int + expected bool + description string +}{ + {2015, false, "year not divisible by 4: common year"}, + {1996, true, "year divisible by 4, not divisible by 100: leap year"}, + {2100, false, "year divisible by 100, not divisible by 400: common year"}, + {2000, true, "year divisible by 400: leap year"}, + {1800, false, "year divisible by 200, not divisible by 400: common year"}, +} diff --git a/leap.go b/leap.go new file mode 100644 index 0000000..f5e9896 --- /dev/null +++ b/leap.go @@ -0,0 +1,18 @@ +package leap + +const testVersion = 2 + +// IsLeapYear receives an integer year value and returns a boolean indicating +// whether the year is a leap year or not. +func IsLeapYear(year int) bool { + switch { + case year%400 == 0: + return true + case year%100 == 0: + return false + case year%4 == 0: + return true + default: + return false + } +} \ No newline at end of file diff --git a/leap_test.go b/leap_test.go new file mode 100644 index 0000000..eabd1f2 --- /dev/null +++ b/leap_test.go @@ -0,0 +1,22 @@ +package leap + +import "testing" + +func TestLeapYears(t *testing.T) { + for _, test := range testCases { + observed := IsLeapYear(test.year) + if observed != test.expected { + t.Fatalf("IsLeapYear(%d) = %t, want %t (%s)", + test.year, observed, test.expected, test.description) + } + } +} + +// Benchmark 400 year interval to get fair weighting of different years. +func Benchmark400(b *testing.B) { + for i := 0; i < b.N; i++ { + for y := 1600; y < 2000; y++ { + IsLeapYear(y) + } + } +}