What is the correct way to obtain (-1)^n?

Question

Many algorithms require to compute (-1)^n (both integer), usually as a factor in a series. That is, a factor that is -1 for odd n and 1 fo

Answer 1

What about

(1 - (n%2)) - (n%2)

n%2 most likely will be computed only once

UPDATE

Actually, simplest and most correct way would be using table

const int res[] {-1, 1, -1};

return res[n%2 + 1];