Turn off the rightmost set bit

reference: 

http://www.geeksforgeeks.org/turn-off-the-rightmost-set-bit/

Problem Definition:

Write a C function that unsets the rightmost set bit of an integer.

Solution:

Let the input number be n. n-1 would have all the bits flipped after the rightmost set bit (including the set bit). So, doing n&(n-1) would give us the required result.

Code:

/* unsets the rightmost set bit of n and returns the result */
int fun(unsigned int n)
{
  return n&(n-1);
}