What are the required steps to convert base 10 integer
number -68 374 838 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:
|-68 374 838| = 68 374 838
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;
- 68 374 838 ÷ 2 = 34 187 419 + 0;
- 34 187 419 ÷ 2 = 17 093 709 + 1;
- 17 093 709 ÷ 2 = 8 546 854 + 1;
- 8 546 854 ÷ 2 = 4 273 427 + 0;
- 4 273 427 ÷ 2 = 2 136 713 + 1;
- 2 136 713 ÷ 2 = 1 068 356 + 1;
- 1 068 356 ÷ 2 = 534 178 + 0;
- 534 178 ÷ 2 = 267 089 + 0;
- 267 089 ÷ 2 = 133 544 + 1;
- 133 544 ÷ 2 = 66 772 + 0;
- 66 772 ÷ 2 = 33 386 + 0;
- 33 386 ÷ 2 = 16 693 + 0;
- 16 693 ÷ 2 = 8 346 + 1;
- 8 346 ÷ 2 = 4 173 + 0;
- 4 173 ÷ 2 = 2 086 + 1;
- 2 086 ÷ 2 = 1 043 + 0;
- 1 043 ÷ 2 = 521 + 1;
- 521 ÷ 2 = 260 + 1;
- 260 ÷ 2 = 130 + 0;
- 130 ÷ 2 = 65 + 0;
- 65 ÷ 2 = 32 + 1;
- 32 ÷ 2 = 16 + 0;
- 16 ÷ 2 = 8 + 0;
- 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.
68 374 838(10) = 100 0001 0011 0101 0001 0011 0110(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 27.
- 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, 27,
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:
68 374 838(10) = 0000 0100 0001 0011 0101 0001 0011 0110
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...
-68 374 838(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-68 374 838(10) = 1000 0100 0001 0011 0101 0001 0011 0110
Spaces were used to group digits: for binary, by 4, for decimal, by 3.