COMPLEMENTS IN COMPUTER STUDIES

THE ONE'S COMPLEMENTS

One's complement or Inverse code is simply inverted binary code of a number. That is all zeroes become ones and all ones become zeroes. It is very useful in computer engineering.

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Original	One's Complement
00000000	11111111
10011001	01100110
10000001	01111110
11110000	00001111
11111111	00000000

one can say, the 1’s complement of a binary number is found by changing all 1s to 0s and all 0s to 1s as shown below


THE TWO;S COMPLEMENTS

This is a decimal/binary to two’s complement converter and a two’s complement to decimal converter. It is a system in which the negative numbers are represented by the two’s complement of the absolute value. For example, -9 converts to 11110111 (to 8 bits), which is -9 in two’s complement. Complementing it would make it 9, or 00001001 to 8 bits

The two’s complement is a method for representing positive and negative integer values in the decimal number system. The two’s complement automatically includes the sign bit.
If input number is a decimal number(with or without sign) then we covert decimal number into binary number else we first form the one's complement for given binary number and then add 1 to the one’s complement.
Step 1: Begin with the binary value
           10011001
Step 2: Formed the one's complement as follows:
           01100110
Step 3: Add 1 to the one's complement
           01100110 (One's complement)
                     + 1 (Add 1)
           -----------
           01100111 (Two's complement)