Good morning,
I am given the hamming distance algorithm in C which is
I see that this loop counts all the 1's that are found when we xor y and x, but what I'm puzzled with is how does the while loop break out? How does it know when a value is complete?Code:int returnDistance(int x, int y) { unsigned dist = 0; unsigned val = x ^ y; while(val) { ++dist; val &= val - 1; } return dist; }
Thanks.
Print out the value of val in the loop and observe what happens for various input. Alternatively, just observe by using a debugger.
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
As I can see, the expression:
Removes one bit from val (sets one of them, which is 1, to 0). After a few iterations all bits will be set to 0. The loop breaks when val == 0 (all bits are 0).Code:val &= val - 1;
