Bits Facts and Tricks
x ^ 0s = x
x & 0s = 0
x | 0s = x
x ^ 1s = ~x
x & 1s = x
x | 1s = 1s
x ^ x = 0
x & x = x
x | x = x
Common Bit Tasks: Get, Set, Clear And Update
Get: num & (1 << i) != 0
Set: num | (1 << i)
Clear：
clear ith bit: num & (~(1 << i))
clear all bits from the most significant bit through i: num & ((1 << i) - 1)
clear all bits from i though 0: num & (~((1 << (i + 1)) - 1))
Update: (num & (~(1 << i))) | (v << i)
5.4
1 ((n & (n - 1)) == 0) //check if n is a power of 2 (or if n is 0)
5.5 Swap odd and even bits in an integer with as few instructions ad possible.
1 //0xaaaaaa is 1010101010 which mask all odd bits 2 public int swapOddEven(int x){ 3 return ( ((x & 0xaaaaaaaa) >> 1) | ((x & 0x55555555) << 1) ); 4 }