One's Complement: Binary ↘ Integer: 0000 0000 0000 1111 1111 0000 0000 1111 Signed Binary Number in One's Complement Representation, Converted and Written as a Decimal System Integer (in Base Ten)

Signed binary in one's complement representation 0000 0000 0000 1111 1111 0000 0000 1111(2) converted to an integer in decimal system (in base ten) = ?

1. Is this a positive or a negative number?

0000 0000 0000 1111 1111 0000 0000 1111 is the binary representation of a positive integer, on 32 bits (4 Bytes).


In a signed binary in one's complement representation, the first bit (the leftmost) indicates the sign, 1 = negative, 0 = positive.


2. Get the binary representation of the positive (unsigned) number.

* Run this step only if the number is negative *

Flip all the bits of the signed binary in one's complement representation (reverse the digits) - replace the bits set on 1 with 0s and the bits on 0 with 1s:

* Not the case - the number is positive *


3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:

  • 231

    0
  • 230

    0
  • 229

    0
  • 228

    0
  • 227

    0
  • 226

    0
  • 225

    0
  • 224

    0
  • 223

    0
  • 222

    0
  • 221

    0
  • 220

    0
  • 219

    1
  • 218

    1
  • 217

    1
  • 216

    1
  • 215

    1
  • 214

    1
  • 213

    1
  • 212

    1
  • 211

    0
  • 210

    0
  • 29

    0
  • 28

    0
  • 27

    0
  • 26

    0
  • 25

    0
  • 24

    0
  • 23

    1
  • 22

    1
  • 21

    1
  • 20

    1

4. Multiply each bit by its corresponding power of 2 and add all the terms up.

0000 0000 0000 1111 1111 0000 0000 1111(2) =


(0 × 231 + 0 × 230 + 0 × 229 + 0 × 228 + 0 × 227 + 0 × 226 + 0 × 225 + 0 × 224 + 0 × 223 + 0 × 222 + 0 × 221 + 0 × 220 + 1 × 219 + 1 × 218 + 1 × 217 + 1 × 216 + 1 × 215 + 1 × 214 + 1 × 213 + 1 × 212 + 0 × 211 + 0 × 210 + 0 × 29 + 0 × 28 + 0 × 27 + 0 × 26 + 0 × 25 + 0 × 24 + 1 × 23 + 1 × 22 + 1 × 21 + 1 × 20)(10) =


(0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 524 288 + 262 144 + 131 072 + 65 536 + 32 768 + 16 384 + 8 192 + 4 096 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 8 + 4 + 2 + 1)(10) =


(524 288 + 262 144 + 131 072 + 65 536 + 32 768 + 16 384 + 8 192 + 4 096 + 8 + 4 + 2 + 1)(10) =


1 044 495(10)

5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:

0000 0000 0000 1111 1111 0000 0000 1111(2) = 1 044 495(10)

The signed binary number in one's complement representation 0000 0000 0000 1111 1111 0000 0000 1111(2) converted and written as an integer in decimal system (base ten):
0000 0000 0000 1111 1111 0000 0000 1111(2) = 1 044 495(10)

Spaces were used to group digits: for binary, by 4, for decimal, by 3.

The latest binary numbers in one's complement representation converted to signed integers numbers written in decimal system (base ten)

How to convert signed binary numbers in one's complement representation from binary system to decimal

To understand how to convert a signed binary number in one's complement representation from binary system to decimal (base ten), the easiest way is to do it through an example - convert binary, 1001 1101, to base ten:

  • In a signed binary one's complement, first bit (leftmost) indicates the sign, 1 = negative, 0 = positive. The first bit is 1, so our number is negative.
  • Get the binary representation of the positive number, flip all the bits in the signed binary one's complement representation (reversing the digits) - replace the bits set on 1 with 0s and the bits on 0 with 1s:
    !(1001 1101) = 0110 0010
  • Write bellow the positive binary number representation in base two, and above each bit that makes up the binary number write the corresponding power of 2 (numeral base) that its place value represents, starting with zero, from the right of the number (rightmost bit), walking to the left of the number by increasing each corresonding power of 2 by exactly one unit:
  • powers of 2: 7 6 5 4 3 2 1 0
    digits: 0 1 1 0 0 0 1 0
  • Build the representation of the positive number in base 10, by taking each digit of the binary number, multiplying it by the corresponding power of 2 and then adding all the terms up:

    0110 0010(2) =


    (0 × 27 + 1 × 26 + 1 × 25 + 0 × 24 + 0 × 23 + 0 × 22 + 1 × 21 + 0 × 20)(10) =


    (0 + 64 + 32 + 0 + 0 + 0 + 2 + 0)(10) =


    (64 + 32 + 2)(10) =


    98(10)

  • Signed binary number in one's complement representation, 1001 1110 = -98(10), a signed negative integer in base 10