# very basic question

priya selva

Greenhorn

Posts: 29

Dave Vick

Ranch Hand

Posts: 3244

posted 14 years ago

Priya

To use your number as an example:

7 in binary is

00000000 00000000 00000000 000000111

to get a negative number you flip all of the bits (turn all of the 1s into 0s and all of the 0s into 1s) then add 1 to the result.

To change 7 into -7:

So, the binary number 11111111 11111111 11111111 111111001, is the same as -7 in decimal.

Does that help?

To use your number as an example:

7 in binary is

00000000 00000000 00000000 000000111

to get a negative number you flip all of the bits (turn all of the 1s into 0s and all of the 0s into 1s) then add 1 to the result.

To change 7 into -7:

So, the binary number 11111111 11111111 11111111 111111001, is the same as -7 in decimal.

Does that help?

Dave

Greg Ostravich

Ranch Hand

Posts: 112

posted 14 years ago

There's a Cat and Mouse game with Bits on JavaRanch you may want to check out.

It's easiest to flip the bits and add one to get a negative number.

Here's another way to look at it.

If you substract the highest bit from the rest and negate it.

I'm rusty on bits but here's some examples:

[ August 14, 2002: Message edited by: Greg Ostravich ]

[ August 14, 2002: Message edited by: Greg Ostravich ]

It's easiest to flip the bits and add one to get a negative number.

Here's another way to look at it.

If you substract the highest bit from the rest and negate it.

I'm rusty on bits but here's some examples:

[ August 14, 2002: Message edited by: Greg Ostravich ]

[ August 14, 2002: Message edited by: Greg Ostravich ]

Greg Ostravich - SCPJ2