# To find complement of a number

Discussion in 'C++' started by vijaybaskar3108, Mar 25, 2007.

1. hi,
I just want to know how to find complements for a number.
These are the following answers for complements
2's complement(10110)=01010
4's complement(1230)=2110
5's complement(4322)=0123
please tell me how to do it.how this answers comes.This is a global
edge question.
please also tell me how to find 8's complement(7436)
please alos tell me how to find 3's,4's,5's,6's,7's,8's complements.
regards
vijay

2. ### =?ISO-8859-1?Q?Erik_Wikstr=F6m?=Guest

Doesn't you textbook tell you that? And have you tried google? And what
part of the questions concern C++? (Perhaps comp.programming would be
more useful.) Before making your next post take a little while to read
http://www.parashift.com/c++-faq-lite/how-to-post.html, sections 5.2 and
5.9 might be of special interest.

=?ISO-8859-1?Q?Erik_Wikstr=F6m?=, Mar 25, 2007

3. ### Alexander D. B. KimGuest

Hi there,

The principle of making a compliment number is quite simple like
binary calculation.

If you wanna make a 2's compliment of 10110, it is 01010 because when
you make a sum of 10110 and 01010 , the result becomes 100000.
However, the digits were only 5 bits so we don't care about the 1 in
the front. In addition, both number must be based on the same number
system.

Here is another example...

Let's do the 8's complement of 7436. 7436 is a number of base 8 so try
to make 1 0000 in this time.

7436(8) + 4(8) = 7440 (8)
7440(8) + 40(8) = 7500 (8)
7500(8) + 500(8) = 10000 (8)

so the 8's complement of 7436 is 0544(8).

Does it make sense to you?

I hope you understand this.

Cheers,

Alexander D. B. Kim, Mar 25, 2007
4. ### Alexander D. B. KimGuest

You're little bit mean, mate =P Quire right though. =)

Cheers,

Alexander D. B. Kim, Mar 25, 2007
5. ### Marvin825

Joined:
Aug 1, 2012
Messages:
1
0
Question? Shouldn't it be 564? Instead of 544?
He made a mistake in adding 7440 to make it 7500. Just want to inform you guys. Am studying the diminished radix and radix complement this semester. Marvin825, Aug 1, 2012
6. ### R.Mahima

Joined:
Oct 26, 2019
Messages:
1
0
In octal , the decimal numbers 8 and 9 are represented as 10 and 11 .

Octal decimal
00 00
01 01
02 02
03 03
04 04
05 05
06 06
07 07
10 08
11 09
12 10
13 11
14 12
15 13
16 14
17 15​
So it means if you add 7440 and 40 in octal you get 7500☺

R.Mahima, Oct 26, 2019