some tricky questions on bit manupulation:

1.Write a program to swap odd and even bits in an integer with as few instructions as possible (e.g., bit 0 and bit 1 are swapped, bit 2 and bit 3 are swapped, etc).


ans:Mask all odd bits with 10101010 in binary (which is 0xAA), then shift them left to put them in the even bits. Then, perform a similar operation for even bits. This takes a total 5 instructions.
public static int swapOddEvenBits(int x)
 {
return ( ((x & 0xaaaaaaaa) >> 1) | ((x & 0x55555555) << 1) );
}


2.An inline function to test whether a number is power of 2?

ans:((n & (n-1)) == 0).