Question

How does the following code work and what do the variables mean:

y = (x << shift) | (x >> (sizeof(x)*CHAR_BIT - shift));

I found in a circular shift article but with no explanation on how this works.

Answer 1

CHAR_BIT is the number of bits per byte, should be 8 always.

shift is the number of bits you want to shift left in a circular fashion, so the bits that get shifted out left, come back on the right.

     1110 0000 << 2 results in:
     1000 0011

code for the example:

   y = (x << 2) | (x >> (8 - 2));