8-bit 2s complement representation of -19 is 11101101

For 1s complement invert all the bits.

For 2s complement add 1 to the 1s complement:

With 8-bits:

19 � 0001 0011

1s � 1110 1100

2s � 1110 1100 + 1 = 1110 1101

The bitwise complement or one's complement operator (~) is used to switch the state of all the bits in a value. Thus 1's become 0, and 0's become 1.

One of its many uses is to unset individual bit(s) in a bitmap. We do this with a bitwise AND of the bitmap and the bitwise complement of the bit(s) we want to unset.

Original bitmap: 01011100

Bit to unset: 00000100 (e.g., bit 2 (bits are zero based from right))

// Using one's complement and bitwise AND

~00000100 & 01011100

11111011 (one's complement of bit 2)

&

01011100 (original bitmap)

=

01011000 (original bitmap with bit 2 unset)

Note that this formula works even if bit 2 were already unset:

11111011 (one's complement of bit 2)

&

01011000 (original bitmap, with bit 2 unset)

=

01011000 (original bitmap unchanged)

ANSWER: MSB IS 1

In the 2's complement representation, the 2's complement of a binary number is obtained by first finding the one's complement (flipping all the bits), and then adding 1 to the result. This representation is commonly used to represent signed integers in binary form.

Now, if all bits except the sign bit are the same, taking the 2's complement of the binary number will result in the negative of the original number. The sign bit (the leftmost bit) is flipped, changing the sign of the entire number.

For example, let's take the 4-bit binary number

1101

1101. The 2's complement would be obtained as follows:

Find the one's complement:

0010

Add 1 to the one's complement:

0011

-128 to 127, in two's-complement.

-128 to 127, in two's-complement.