How does C++ do bitwise “or” operations on negative numbers?

Question

When I give to a variable such value: e = 17|-15; , I get -15 as an answer after compiling.I can\'t understand what arithmetic c++ uses. How does it perform a

Answer 1

you have to looks at how the bits work

Basically, if either number has a 1 in a particular spot, than the result will also have a 1

-15       : 11110001 (two's complement)
17        : 00010001
-15 | 17  : 11110001

as you can see, the result is the same as -15