What are the required steps to convert base 10 integer
number -1 155 085 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:
|-1 155 085| = 1 155 085
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;
- 1 155 085 ÷ 2 = 577 542 + 1;
- 577 542 ÷ 2 = 288 771 + 0;
- 288 771 ÷ 2 = 144 385 + 1;
- 144 385 ÷ 2 = 72 192 + 1;
- 72 192 ÷ 2 = 36 096 + 0;
- 36 096 ÷ 2 = 18 048 + 0;
- 18 048 ÷ 2 = 9 024 + 0;
- 9 024 ÷ 2 = 4 512 + 0;
- 4 512 ÷ 2 = 2 256 + 0;
- 2 256 ÷ 2 = 1 128 + 0;
- 1 128 ÷ 2 = 564 + 0;
- 564 ÷ 2 = 282 + 0;
- 282 ÷ 2 = 141 + 0;
- 141 ÷ 2 = 70 + 1;
- 70 ÷ 2 = 35 + 0;
- 35 ÷ 2 = 17 + 1;
- 17 ÷ 2 = 8 + 1;
- 8 ÷ 2 = 4 + 0;
- 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.
1 155 085(10) = 1 0001 1010 0000 0000 1101(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 21.
- 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, 21,
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:
1 155 085(10) = 0000 0000 0001 0001 1010 0000 0000 1101
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...
-1 155 085(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-1 155 085(10) = 1000 0000 0001 0001 1010 0000 0000 1101
Spaces were used to group digits: for binary, by 4, for decimal, by 3.