Ashutosh

• Nov 7th, 2005

 

& operator

Ajay Kanse

 Profile Answers by Ajay Kanse Questions by Ajay Kanse

• Jul 1st, 2007

 

Bitwise OR - | is the correct answer- x = x | SET_ON

Sudheendra.S.N

 Profile Answers by Sudheendra.S.N 

• Sep 11th, 2008

 

XOR Operator is right. XOR the given bit with 1 if the bit is 1 then 0 is the o/p else 1 is the o/p.

navneetgoyal2000

 Profile Answers by navneetgoyal2000 Questions by navneetgoyal2000

• Jan 5th, 2011

 

Its Bitwise AND (&)

for Ex, 

I need to check if 3rd bit from right(Starting from 0th) is ON in a variable x or OFF.

then see this code:

int x=24;

int tester=1;

tester = tester << 3; \Makes tester as 00001000

if((x&tester)!=1)

printf("3rd bit from left in x is ON");

else

printf("3rd bit from left in x is OFF");

Explaination:

x = 24 i.e.          0001 1000

tester = 1 i.e.    0000 0001

tester = tester << 3 does:

tester = 8 i.e.    0000 1000

now x&tester i.e.

0001 1000

&&&&&&&&

0000 1000

-------------

0000 1000

which is NON ZERO, hence decides that 3rd bit is SET / ON.

if x = 5 (0000 0101)

then x&tester i.e.

00000101   &

00001000

------------

00000000

which is ZERO, hence decides that 3rd bit is UNSET / OFF.

In Brief:

Bitwise AND is used to CHECK / TEST a particular bit.

Bitwise OR is used to SET (Make it 1) a particular bit.

Bitwise XOR is used to TOGGLE (1to0 or 0to1) a particular bit.

Bitwise AND is also used to RESET a particular bit (if ANDed with 11110111, say I have to reset 4th bit).