Use the modulo (%) operator to create an alternating value.

a ::: a%2

1 ::: 1

2 ::: 0

3 ::: 1

4 ::: 0

5 ::: 1

if (a%2==0) ...

I need an algorithm that calculates 1-1/2+1/3...(or-)1/n for any given n. 1/k is added to the sum if k is odd and subtracted from the sum if k is even.

If someone can assist me and explain to me how you did it, I would love you.