Bit rotation...

How do you rotate bits in C++?

I think i know a bitshift ( >> ) right? But that clips off the edges dont it?


Any help would be appreciated! Thanks!

Catch the bits which would fall off the end, then add them back in yourself.

They have to be rotated every 5,000 miles or they will wear prematurely. Also be sure to keep your bits properly inflated for better fuel efficiency.

Originally Posted by Junior89

How do you rotate bits in C++?

I think i know a bitshift ( >> ) right? But that clips off the edges dont it?


Any help would be appreciated! Thanks!

Assuming chars are octets:

Code:

unsigned char rotate_left(unsigned char v, int n)
{
    return (v << n) | (v >> (8 - n) );
}

Same basic idea for other size types. Always use unsigned types for this.

Originally Posted by brewbuck

Assuming chars are octets:

Code:

unsigned char rotate_left(unsigned char v, int n)
{
    return (v << n) | (v >> (8 - n) );
}

Same basic idea for other size types. Always use unsigned types for this.

Easily generalized for all char implementations with

Code:

 return (v << n) | (v >> (std::numeric_limits<char>::digits - n) );