Sep

How to set, clear ,toggle and check a single bit in C?

JIGAR PATEL Category

As being an embedded software engineer i would really suggest you this tricks. ..! In many application you need to deal with this bit wise operation. Sometimes you know this all stuff very well but still some time it takes time to construct this logic or some time you got some mistakes in it. so i suggest you to paste this on your desk until you paste this in your mind..!

To set a bit

Use the bitwise OR operator (|) to set a bit.

 number |= 1 << x;

That will set bit x.

To clear a bit

Use the bitwise AND operator (&) to clear a bit.

 number &= ~(1 << x);

That will clear bit x. You must invert the bit string with the bitwise NOT operator (~), then AND it.

To toggle a bit

The XOR operator (^) can be used to toggle a bit.

 number ^= 1 << x;

That will toggle bit x.

To check state of a bit

To check a bit, AND it with the bit you want to check:

 bit = number & (1 << x);

That will put the value of bit x into the variable bit.

NOTE : here x is the position of bit starting from 0 to LSB.

JIGAR PATEL

hey I am an Artist who love to write code…! Well I am an EC graduate From Ganpat University and now i am working as Embedded software engineer in one private firm.. find me at here JigAr Patel

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2 Comments to “How to set, clear ,toggle and check a single bit in C?”

diablo 3 October 22, 2011 at 6:49 am
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Rahul March 3, 2013 at 8:24 am
Seriously just one comment on such a good post ? There’s one question though. Why XOR ? Why not use the NOT operator ?

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