CHow-ToBeginner · 4 min read

How to Use Bitwise Operators in C: Syntax and Examples

In C, bitwise operators like &, |, ^, ~, <<, and >> manipulate individual bits of integers. Use them to perform operations such as AND, OR, XOR, NOT, left shift, and right shift directly on binary representations.

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Syntax

Bitwise operators work on integer types and manipulate bits directly:

&: Bitwise AND
|: Bitwise OR
^: Bitwise XOR (exclusive OR)
~: Bitwise NOT (inverts bits)
<<: Left shift (shifts bits left)
>>: Right shift (shifts bits right)

Operands are integers, and the result is an integer with bits changed accordingly.

result = a & b;  // Bitwise AND
result = a | b;  // Bitwise OR
result = a ^ b;  // Bitwise XOR
result = ~a;     // Bitwise NOT
result = a << 2; // Left shift by 2 bits
result = a >> 3; // Right shift by 3 bits

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Example

This example shows how to use bitwise operators to combine and modify bits of two numbers.

#include <stdio.h>

int main() {
    unsigned int a = 5;  // binary: 0101
    unsigned int b = 9;  // binary: 1001

    printf("a & b = %u\n", a & b);  // AND
    printf("a | b = %u\n", a | b);  // OR
    printf("a ^ b = %u\n", a ^ b);  // XOR
    printf("~a = %u\n", ~a);        // NOT
    printf("a << 1 = %u\n", a << 1); // Left shift
    printf("b >> 2 = %u\n", b >> 2); // Right shift

    return 0;
}

Output

a & b = 1 a | b = 13 a ^ b = 12 ~a = 4294967290 a << 1 = 10 b >> 2 = 2

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Common Pitfalls

Common mistakes when using bitwise operators include:

Using bitwise operators instead of logical operators (&&, ||) for conditions.
Not considering signed vs unsigned types, which affects shifts and ~ results.
Shifting bits by a value equal or larger than the bit width (e.g., shifting 32 bits on a 32-bit int).
Forgetting operator precedence, which can cause unexpected results without parentheses.

#include <stdio.h>

int main() {
    int x = 4;  // 0100
    int y = 2;  // 0010

    // Wrong: using bitwise AND instead of logical AND
    if (x & y) {
        printf("Bitwise AND used in condition: true\n");
    }

    // Right: use logical AND
    if (x && y) {
        printf("Logical AND used in condition: true\n");
    }

    return 0;
}

Output

Bitwise AND used in condition: true Logical AND used in condition: true

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Quick Reference

Operator	Description	Example	Result
&	Bitwise AND	5 & 3	1 (0101 & 0011 = 0001)
\|	Bitwise OR	5 \| 3	7 (0101 \| 0011 = 0111)
^	Bitwise XOR	5 ^ 3	6 (0101 ^ 0011 = 0110)
~	Bitwise NOT	~5	4294967290 (inverts bits)
<<	Left shift	5 << 1	10 (0101 << 1 = 1010)
>>	Right shift	5 >> 1	2 (0101 >> 1 = 0010)

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Key Takeaways

Bitwise operators manipulate individual bits of integers for efficient low-level operations.

Use & (AND), | (OR), ^ (XOR), ~ (NOT), << (left shift), and >> (right shift) with integer types.

Avoid confusing bitwise operators with logical operators in conditions.

Be careful with signed vs unsigned types and shift amounts to prevent unexpected results.

Use parentheses to ensure correct operator precedence when combining bitwise operations.