Is there a negative zero?

Question

I\'m coding a simple calculator just to get started with iPhone dev. The thing is I have a (-) button thats supposed to negate whatever is put to the screen

Answer 1

float and double support -0 (which is different than 0 if memory serves). See here for more information, though I'm not convinced using -0 in your application will be particularly helpful for users. Do you have a compelling use case that requires it?

Answer 2

There's no such thing as negative zero.

For a binary integer, setting the sign bit to 1 and all other bits to zero, you get the smallest negative value for that integer size. (Assuming signed numbers.)