C Bitwise Operators – Direct Manipulation of Bits

Bitwise operators in C allow you to manipulate individual bits of data directly. They’re especially useful in systems programming, embedded systems, game development, and performance-critical applications.

Why Use Bitwise Operators?

Bitwise operators:

Perform operations faster than arithmetic.
Help in flags, masks, compression, and encryption.
Give low-level control over data and memory.

List of Bitwise Operators in C

Operator	Name	Description
`&`	AND	Sets each bit to 1 if both bits are 1
`	`	OR
`^`	XOR	Sets each bit to 1 if only one is 1
`~`	NOT	Inverts all the bits
`<<`	Left Shift	Shifts bits left, filling with 0 on the right
`>>`	Right Shift	Shifts bits right, preserving sign on left

Bitwise AND (&)

int a = 5;  // 0101
int b = 3;  // 0011
int result = a & b; // 0001 → 1

Bitwise OR (|)

int a = 5;  // 0101
int b = 3;  // 0011
int result = a | b; // 0111 → 7

Bitwise NOT (~)

int a = 5;  // 0101
int result = ~a; // 1010 → -6 (in 2's complement for 4 bits)

Left Shift (<<)

int a = 3;  // 0011
int result = a << 2; // 1100 → 12

Right Shift (>>)

int a = 12; // 1100
int result = a >> 2; // 0011 → 3

Complete Code Example

#include <stdio.h>

int main() {
    int a = 5, b = 3;

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

    return 0;
}

Output:

Best Practices

Tip	Why it Matters
Use with `unsigned` for clarity	Avoids sign-related issues with shifts
Use masks with `&` and `	`
Avoid unnecessary shifting large values	Can lead to undefined behavior

Common Mistakes

Mistake	Problem
Using signed int with shifts	May cause unexpected results
Forgetting parentheses	Bitwise has lower precedence than comparison
Misunderstanding `~a`	Returns 2’s complement, not just flipped bits