What are the required steps to convert base 10 integer
number -665 721 374 to signed binary code (in base 2)?
- A signed integer, written in base ten, or a decimal system number, is a number written using the digits 0 through 9 and the sign, which can be positive (+) or negative (-). If positive, the sign is usually not written. A number written in base two, or binary, is a number written using only the digits 0 and 1.
1. Start with the positive version of the number:
|-665 721 374| = 665 721 374
2. Divide the number repeatedly by 2:
Keep track of each remainder.
Stop when you get a quotient that is equal to zero.
- division = quotient + remainder;
- 665 721 374 ÷ 2 = 332 860 687 + 0;
- 332 860 687 ÷ 2 = 166 430 343 + 1;
- 166 430 343 ÷ 2 = 83 215 171 + 1;
- 83 215 171 ÷ 2 = 41 607 585 + 1;
- 41 607 585 ÷ 2 = 20 803 792 + 1;
- 20 803 792 ÷ 2 = 10 401 896 + 0;
- 10 401 896 ÷ 2 = 5 200 948 + 0;
- 5 200 948 ÷ 2 = 2 600 474 + 0;
- 2 600 474 ÷ 2 = 1 300 237 + 0;
- 1 300 237 ÷ 2 = 650 118 + 1;
- 650 118 ÷ 2 = 325 059 + 0;
- 325 059 ÷ 2 = 162 529 + 1;
- 162 529 ÷ 2 = 81 264 + 1;
- 81 264 ÷ 2 = 40 632 + 0;
- 40 632 ÷ 2 = 20 316 + 0;
- 20 316 ÷ 2 = 10 158 + 0;
- 10 158 ÷ 2 = 5 079 + 0;
- 5 079 ÷ 2 = 2 539 + 1;
- 2 539 ÷ 2 = 1 269 + 1;
- 1 269 ÷ 2 = 634 + 1;
- 634 ÷ 2 = 317 + 0;
- 317 ÷ 2 = 158 + 1;
- 158 ÷ 2 = 79 + 0;
- 79 ÷ 2 = 39 + 1;
- 39 ÷ 2 = 19 + 1;
- 19 ÷ 2 = 9 + 1;
- 9 ÷ 2 = 4 + 1;
- 4 ÷ 2 = 2 + 0;
- 2 ÷ 2 = 1 + 0;
- 1 ÷ 2 = 0 + 1;
3. Construct the base 2 representation of the positive number:
Take all the remainders starting from the bottom of the list constructed above.
665 721 374(10) = 10 0111 1010 1110 0001 1010 0001 1110(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 30.
- 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) is reserved for 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, 30,
3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)
=== is: 32.
5. 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:
665 721 374(10) = 0010 0111 1010 1110 0001 1010 0001 1110
6. Get the negative integer number representation:
To get the negative integer number representation on 32 bits (4 Bytes),
... change the first bit (the leftmost), from 0 to 1...
-665 721 374(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-665 721 374(10) = 1010 0111 1010 1110 0001 1010 0001 1110
Spaces were used to group digits: for binary, by 4, for decimal, by 3.