common bitwise operations

To set the n-th bit:

num |= 1UL << n;

To clear the n-th bit:

num &= ~(1UL << n);

To toggle the n-th bit:

num ^= 1UL << n;

To check if n-th bit is set:

bit = (num >> n) & 1U;

To set the n-th bit to x in two’s complement:

num ^= (-x ^ num) & (1UL << n);

To set the n-th bit to x (regardless of representation):

num ^= (-(unsigned long)x ^ num) & (1UL << n);

Alternatively use a bitset.