I had an exam in DLD subject. There was a question as "Design a circuit which can take 2’s compliment of any 3 bit number". The truth table we get is :
A| B| C|
0| 0| 0|
0| 0| 1|
0| 1| 0|
0| 1| 1|
1| 0| 0|
1| 0| 1|
1| 1| 0|
1| 1| 1|
Whereas when we find 2s complement as
000
111
+1
----
1000
But I have watched many videos where they have ignored 1 and wrote the answer in 3 bits as
A|B|C
0|0|0
Iam much confusing why they ignored 1 and what is the problem if we put 1 rather than ignoring