Essential Bitwise Operators to Know for Intro to C Programming

Bitwise operators in C allow you to manipulate individual bits of data directly. They are essential for tasks like masking, toggling, and setting flags, making them powerful tools for efficient programming and low-level data handling.

1. Bitwise AND (&)

   • Compares each bit of two operands; results in 1 only if both bits are 1.
   • Commonly used for masking bits to isolate specific bits in a number.
   • Example:

     5 & 3

     results in

     1

     (binary:

     0101 & 0011 = 0001

     ).

2. Bitwise OR (|)

   • Compares each bit of two operands; results in 1 if at least one of the bits is 1.
   • Useful for setting specific bits to 1 without affecting others.
   • Example:

     5 | 3

     results in

     7

     (binary:

     0101 | 0011 = 0111

     ).

3. Bitwise XOR (^)

   • Compares each bit of two operands; results in 1 if the bits are different.
   • Often used for toggling bits or checking for differences.
   • Example:

     5 ^ 3

     results in

     6

     (binary:

     0101 ^ 0011 = 0110

     ).

4. Bitwise NOT (~)

   • Inverts all bits of the operand; 0 becomes 1 and 1 becomes 0.
   • Useful for creating a complement of a binary number.
   • Example:

     ~5

     results in

     -6

     (binary:

     ~0101 = 1010

     in two's complement).

5. Left shift (<<)

   • Shifts all bits of the operand to the left by a specified number of positions.
   • Each left shift effectively multiplies the number by 2.
   • Example:

     5 << 1

     results in

     10

     (binary:

     0101 << 1 = 1010

     ).

6. Right shift (>>)

   • Shifts all bits of the operand to the right by a specified number of positions.
   • Each right shift effectively divides the number by 2 (for positive numbers).
   • Example:

     5 >> 1

     results in

     2

     (binary:

     0101 >> 1 = 0010

     ).

7. Bitwise assignment operators (&=, |=, ^=, <<=, >>=)

   • Combine bitwise operations with assignment for concise code.

   • x &= y

     is equivalent to

     x = x & y

     , and similarly for other operators.
   • Useful for updating values based on bitwise operations without redundancy.

8. Bitmasking

   • Technique to manipulate specific bits in a number using masks.
   • Masks are created using bitwise operators to isolate or modify bits.
   • Commonly used in graphics, permissions, and flags.

9. Bit manipulation techniques

   • Techniques include setting, clearing, toggling, and checking bits.
   • Essential for efficient low-level programming and performance optimization.
   • Examples:

     x |= (1 << n)

     sets the nth bit,

     x &= ~(1 << n)

     clears it.

10. Bitwise operations for flag setting and checking

    • Flags are represented as bits in a binary number, allowing multiple states in a single variable.
    • Use bitwise operators to set, clear, or check flags efficiently.
    • Example:

      flags |= FLAG_A

      sets FLAG_A, while

      flags & FLAG_A

      checks if FLAG_A is set.