Give a single line "C type" expression to evaluate (-1)^k using only +,-,* and % operators.

(In reply to Solution by Kurious)

And how does it evaluate when k is not an integer?

(-1)^k,
where k=1/n : n is an odd positive integer > 1, is equal to -1

1-k%2*2,
where k=1/n : n is an odd positive integer > 1, is not equal to -1

Also note: where n is an even positive integer, (-1)^k becomes an imaginary number. 

Other considerations are where k = m/n, such that m/n is a reduced fraction.  Many applications have trouble providing anything other than an error message or like.
How can we then evaluate (-1)^k using only the operators + (addition), - (subtraction), * (multiplication) and % (modulo)? 

Edited on January 28, 2008, 1:10 pm

Posted by Dej Mar on 2008-01-27 22:17:06