Bitwise Operators in C

What Are Bitwise Operators?

Bitwise operators treat data as a collection of bits (0s and 1s). Instead of working on whole numbers, they manipulate individual bits.

• Very fast (used in performance-critical code)
• Operate only on integers
• Useful in flags, masks, drivers, hardware control

List of Bitwise Operators

&   → Bitwise AND  
|   → Bitwise OR  
^   → Bitwise XOR  
~   → Bitwise NOT (One’s complement)  
<<  → Left Shift  
>>  → Right Shift

1. Bitwise AND (&)

Sets a bit to 1 only if both bits are 1.

10 & 7  
1010  
0111  
----  
0010 (2)

2. Bitwise OR (|)

Sets a bit to 1 if any one of the bits is 1.

10 | 5  
1010  
0101  
----  
1111 (15)

3. Bitwise XOR (^)

Sets bit to 1 if bits are different.

10 ^ 5  
1010  
0101  
----  
1111 (15)

4. Bitwise NOT (~)

Flips every bit (0 → 1, 1 → 0).

~5  
00000101  
11111010 ( -6 )     // two’s complement

5. Left Shift (<<)

Shifts bits left and fills 0 on the right.

5 << 2  
00000101  
00010100 (20)

6. Right Shift (>>)

Shifts bits right and fills MSB depending on sign.

20 >> 2  
00010100  
00000101 (5)

Practical Example – All Bitwise Operators

#include <stdio.h>

int main() {

    int a = 10, b = 5;

    printf("AND: %d\n", a & b);
    printf("OR: %d\n", a | b);
    printf("XOR: %d\n", a ^ b);
    printf("NOT: %d\n", ~a);
    printf("Left Shift: %d\n", a << 1);
    printf("Right Shift: %d\n", a >> 1);

    return 0;
}

Useful Real-Life Uses

• Setting or clearing specific bits
• Creating flags & masks
• Checking odd/even (n & 1)
• Fast multiplication/division by 2 (<<, >>)
• Cryptography & hashing
• Microcontroller programming

Practice Questions

1. Explain bitwise XOR with an example.
2. Why are bitwise operators used in embedded systems?
3. What does a << 3 mean?
4. Write differences between AND, OR, XOR.
5. Write a program to count set bits in a number.

Practice Task