The Challenge

In as few characters as possible, find the value of i^n, given n, a positive integer greater than 0. This should be outputted as a String.

For those that don't know, i is the square root of -1. So:

• i^1=i
• i^2=-1
• i^3=-i
• i^4=1

This then repeats..

Rules

• If your language supports complex numbers, don't use any functions or arithmetic that could work this out.
• Floating point inaccuracies are fine for answers that would return decimals anyway, but integer inputs should give exact results

Bonus Points

-5 if you can work the value out where n is also negative

-15 if you can work out the value for any real number (this bonus includes the -5 from the above bonus)

Good luck!