How the tilde calculation happened??

Question

int x=10;
int y = - 10;
System.out.println(~x);
System.out.println(~y);
Output:
-11
9
How the tilde calcution happened??
Can you elaborate it please!!!

Answer 1

basically ~10 in binary is (for a one byte datatype)
~00001010=11110101 which is -11 in decimal but with twos complement its always ~x=-x-1, so yes

Answer 2

yes but if you store it in a variable that is for example 1 byte long it is stored as 0000 1010 because the other 4 bits are filled up with zeros.
if you store it in a 2 byte vaiable it is stored as 0000 0000 0000 1010. because of how the twos complement works out in both cases inverting gives -11. just read the wikipedia article on twos complement

Answer 3

every bit that was 1 is 0 and every bit that is 0 is 1 after ~. because of the way twos complement works ~x = -x -1

Answer 4

Ferdous Rayhan it should be twos complement, not ones complement.
in ones complement ~x=-x
but in your examples ~x=-x-1
all modern processors use twos complement, because it is the most efficient to implement and because you don‘t have to deal with the negative zero problem
so you will almost never stuble across ones complement

Answer 5

10=0000 1010 -> 11110101 which would be -10 in ones complement.
but -11 in twos complement.
you have them mixed up
in ones complement ~x=-x
but in twos complement ~x=-x-1
thats why in ones complement you have two ways to write zero(0 and ~0=-0) but in twos complement only one way

Answer 6

~x= - x-1 is it the rules??
~10=-10-1=-11
~(-10)= -(-10)-1=9..like that??

Answer 7

with your theory ~x=-x-1 its easy but i want to learn in deep .. 10 in binary is 1010..i convert it online..can you explain pi to pi please ..like 1st we got the binary of 10 which is 1010 then we complement it..which is 0101 then for two complement we add 1 with it..then we convert it to decimal..is it correct?? but i did that in converter..it is not right!!

Answer 8

hey...its just ones complement ...i just invert the bytes and convert to the decimal..and it results same as the compiler...not 2s complement...now..after study i know that 2's complement is nothing but adding one with the ones complement....thanks to you a lot...can you say me..when ill need 2s complement and where to use these ones and twos complement...means when ill need to use those or where to use..thank u again

Answer 9

Max i just calculated..look...10=00001010=11110101= -11(~x= -x -1 : ones complement) & 10 =00001010=11110101 +1=11110110= -10(~x=-x :twos complement)....in this way i did same with the int - 10 and 9 ....they were same...and it matched with the compiler...i just converted those signed 8 bit int in mathisfun(dot)com...everything is looking fine now except i got confused hearing you ..can you please check it once more for me please!!!

Answer 10

https://www.mathsisfun.com/binary-decimal-hexadecimal-converter.html here...i put 11110101 and it shows the decimal is - 11....and 11110110 = -10;;;

Answer 11

Max i need a reply...where the mistake

Answer 12

yeah of course, it uses twos complement like everything else. both of the numbers you are inputing are interpreted as twos complement
-11 is 11110101 in twos complement and -10 is 11110110 in twos complement -10 would be 11110101 in ones complement
and -11 would be 11110100 in ones complement