1. Checking Odd/Even

   if (x & 1) { // x is odd } else { // x is even }

2. Clearing the Lowest Set Bit

   x = x & (x — 1);

1. Extracting the Lowest Set Bit

   int lowest = x & -x;

1. Counting Set Bits (Brian Kernighan’s Algorithm)

int count = 0; while (x) { x &= (x — 1);// clear the lowest set bit count++; }

1. XOR Swap Trick

   a ^= b; b ^= a; a ^= b;

1. Converting Case for Letters

   ->Uppercase to Lowercase: char lower = ch | ' ' ;

   ->Lowercase to Uppercase: char upper = ch & '_' ;

1. Next Highest Power of 2

   unsigned int v = original; v--;// in case v is already a power of 2 v |= v >> 1; v |= v >> 2; v |= v >> 4; v |= v >> 8; v |= v >> 16;// For 32-bit integers; extend for 64-bit as needed. v++;

1. Multiply or Divide by Powers of Two

int mul = x << 3; // Multiply x by 8 (2^3) int div = x >> 2; // Divide x by 4 (2^2)

1. Averaging Two Numbers Without Overflow

   int average = (x & y) + ((x ^ y) >> 1);