I have been learning about Bitwise operations today and I learned that Not (~) inverses all bits, e.g.:

01010
to
10101

which means ~10 should be -5 but instead I have seen that it is -11 (per the python command line) which is

01010
to
11011

only two of the bits have been inverted. Can anybody explain why it isn't 10101?

EDIT: After looking on my calculator I understand it a little better, But my own code for determining binary and ints is still being confused. Entering in (in byte mode) 11110101 gives me -11 but the same entered in my code gives -117:

def binaryToInt(biNum, bUnsigned = False):iNum = 0bSign = int(biNum[0]) if not (bUnsigned or biNum[-1] == "u") else 0biNum = biNum[(1 if not (bUnsigned or biNum[-1] == "u") else 0):(len(biNum) if biNum[-1] != "u" else -1)]for i in xrange(len(biNum)):iNum += int(biNum[i]) * 2**(len(biNum) - 1 - i)return (iNum if not bSign else -iNum)def intToBinary(iNum, bUnsigned = False):bSign = "1" if iNum < 0 else "0"iLoopNum = int((iNum ** 2) ** 0.5) #make positive!biNum = ""while iLoopNum:biNum += str(iLoopNum%2)iLoopNum /= 2return bSign + biNum[::-1] if not bUnsigned else biNum[::-1] + "u"

can one of you explain that?

Assuming that values are 32 bits, 10 is

00000000000000000000000000001010

and if you invert all those bits, you get

11111111111111111111111111110101

or -11. Because it's a 2's complement system!