rotating bits

[MDell95]

how can i shift bits without loosing any information... heard something about bit rotating but i'm not really clear how it works... thankful for every answer

[Disch]

rotating bits means to shift in bits that were previously shifted out.

There's no operator for this in C++, but it can be accomplished with bitwise operators:

typedef unsigned char byte;

//...
byte rotateright(byte v)
{
  byte temp = v & 1;  // extract the low bit
  v >>= 1;  // shift right
  v |= (temp << 7); // put the previous low bit in the high bit
  return v;
}

[MDell95]

thanks... but if i want to get the old value by "back-shifting" it i get something else! so by doing:

byte temp1 = v & 1;
v <<= 1;
v |= (temp1 >> 7);

...i don't get the same value as v had befor rotating...

[Gaminic]

Temp1 should be the top bit if you're left-rotating.