> ## Documentation Index > Fetch the complete documentation index at: https://docs.syntblaze.com/llms.txt > Use this file to discover all available pages before exploring further. # C Bitwise XOR Assignment The `^=` operator is the bitwise Exclusive OR (XOR) compound assignment operator in C. It performs a bitwise XOR operation between the left and right operands, and subsequently assigns the resulting value directly back to the left operand. ## Syntax ```c theme={"dark"} lvalue ^= rvalue; ``` This expression is semantically equivalent to: ```c theme={"dark"} lvalue = lvalue ^ (rvalue); ``` However, in the compound assignment (`^=`), the `lvalue` is evaluated only once. This distinction is critical when the left operand contains side effects, such as a function call or a post-increment operator (e.g., `array[i++] ^= 5;`). ## Operands and Type Constraints Both operands must be of integral types (e.g., `char`, `short`, `int`, `long`, `unsigned`). The operator cannot be applied to floating-point types (`float`, `double`) or pointers. During execution, standard integer promotion rules apply. The operands are promoted to a common type before the bitwise operation occurs, and the final result is truncated or converted back to the type of the `lvalue` during assignment. ## Bitwise Mechanics The operator evaluates the operands at the binary level, comparing them bit by bit. For each corresponding bit position, it applies the XOR truth table: * `0 ^ 0 = 0` * `0 ^ 1 = 1` * `1 ^ 0 = 1` * `1 ^ 1 = 0` If the bits at a given position are different, the resulting bit is `1`. If the bits are identical, the resulting bit is `0`. ## Execution Example ```c theme={"dark"} #include int main() { unsigned char a = 12; // Binary representation: 0000 1100 unsigned char b = 10; // Binary representation: 0000 1010 a ^= b; // Modifies 'a' in place /* Bitwise evaluation step-by-step: 0000 1100 (a = 12) ^ 0000 1010 (b = 10) 0000 0110 (Result = 6) */ printf("%d\n", a); // Outputs: 6 return 0; } ```

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