Write a program that will take a year and report if it is a leap year.
The tricky thing here is that a leap year occurs:
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.
For a delightful, four minute explanation of the whole leap year phenomenon, go watch this youtube video.
Go through the project setup instructions for Xcode using Swift:
http://help.exercism.io/getting-started-with-swift.html
JavaRanch Cattle Drive, exercise 3 view source