1. Divide the number repeatedly by 2:
Keep track of each remainder.
We stop when we get a quotient that is equal to zero.
- division = quotient + remainder;
- 21 474 839 ÷ 2 = 10 737 419 + 1;
- 10 737 419 ÷ 2 = 5 368 709 + 1;
- 5 368 709 ÷ 2 = 2 684 354 + 1;
- 2 684 354 ÷ 2 = 1 342 177 + 0;
- 1 342 177 ÷ 2 = 671 088 + 1;
- 671 088 ÷ 2 = 335 544 + 0;
- 335 544 ÷ 2 = 167 772 + 0;
- 167 772 ÷ 2 = 83 886 + 0;
- 83 886 ÷ 2 = 41 943 + 0;
- 41 943 ÷ 2 = 20 971 + 1;
- 20 971 ÷ 2 = 10 485 + 1;
- 10 485 ÷ 2 = 5 242 + 1;
- 5 242 ÷ 2 = 2 621 + 0;
- 2 621 ÷ 2 = 1 310 + 1;
- 1 310 ÷ 2 = 655 + 0;
- 655 ÷ 2 = 327 + 1;
- 327 ÷ 2 = 163 + 1;
- 163 ÷ 2 = 81 + 1;
- 81 ÷ 2 = 40 + 1;
- 40 ÷ 2 = 20 + 0;
- 20 ÷ 2 = 10 + 0;
- 10 ÷ 2 = 5 + 0;
- 5 ÷ 2 = 2 + 1;
- 2 ÷ 2 = 1 + 0;
- 1 ÷ 2 = 0 + 1;
2. Construct the base 2 representation of the positive number:
Take all the remainders starting from the bottom of the list constructed above.
21 474 839(10) = 1 0100 0111 1010 1110 0001 0111(2)
3. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 25.
A signed binary's bit length must be equal to a power of 2, as of:
21 = 2; 22 = 4; 23 = 8; 24 = 16; 25 = 32; 26 = 64; ...
The first bit (the leftmost) indicates the sign:
0 = positive integer number, 1 = negative integer number
The least number that is:
1) a power of 2
2) and is larger than the actual length, 25,
3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)
=== is: 32.
4. Get the positive binary computer representation on 32 bits (4 Bytes):
If needed, add extra 0s in front (to the left) of the base 2 number, up to the required length, 32.
Number 21 474 839(10), a signed integer number (with sign), converted from decimal system (from base 10) and written as a signed binary in two's complement representation:
Spaces were used to group digits: for binary, by 4, for decimal, by 3.