UGC NET CS 2005 Dec-Paper-2

Question 8

Consider the following sequence of instructions :
a=a⊕b, b=a⊕b, a=b⊕a
This Sequence

A	retains the value of the a and b
B	complements the value of a and b
C	swap a and b
D	negates values of a and b

Question 8 Explanation:

⇒ a=a⊕b
⇒ b=a ⊕b
= a⊕b ⊕b (Substitute (1))
= 0 ⊕ b
= b
⇒ a = b⊕a
= b⊕a⊕b (Substitute (1))
= a⊕b⊕b
= a⊕0
= a

Correct Answer: A

Question 8 Explanation:

⇒ a=a⊕b
⇒ b=a ⊕b
= a⊕b ⊕b (Substitute (1))
= 0 ⊕ b
= b
⇒ a = b⊕a
= b⊕a⊕b (Substitute (1))
= a⊕b⊕b
= a⊕0
= a