C Bitwise Operations Cheat Sheet

unsigned int a = 0xA;   // 1010 in binary (10)unsigned int b = 0x6;   // 0110 in binary (6)unsigned int and_result = a & b;   // 0010 = 2   (AND)unsigned int or_result  = a | b;   // 1110 = 14  (OR)unsigned int xor_result = a ^ b;   // 1100 = 12  (XOR)unsigned int not_result = ~a;      // Flips all bits (bitwise NOT)unsigned int left_shift  = a << 2; // 101000 = 40 (multiply by 4)unsigned int right_shift = a >> 1; // 0101 = 5    (divide by 2)

#define FLAG_READ    (1 << 0)   // 0001#define FLAG_WRITE   (1 << 1)   // 0010#define FLAG_EXECUTE (1 << 2)   // 0100unsigned int perms = FLAG_READ | FLAG_WRITE;   // Set multiple flags: 0011perms |= FLAG_EXECUTE;          // Set a flagperms &= ~FLAG_WRITE;            // Clear a flagint has_read = (perms & FLAG_READ) != 0;  // Test a flagperms ^= FLAG_READ;              // Toggle a flag

int is_even = (n & 1) == 0;         // Check even/odd without %int is_power_of_two = n > 0 && (n & (n - 1)) == 0;  // Power-of-two checkint x = 3, y = 5;x ^= y; y ^= x; x ^= y;              // Swap without a temp variable (XOR swap)unsigned int count_set_bits(unsigned int v) {    int count = 0;    while (v) {        v &= (v - 1);   // Clears the lowest set bit each iteration        count++;    }    return count;                   // Brian Kernighan's algorithm}