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What does a bitwise shift (left or right) do and what is it used for?

Asked 2011-06-17T12:35:03.910
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I've seen the operators >> and << in various code that I've looked at (none of which I actually understood), but I'm just wondering what they actually do and what some practical uses of them are.

If the shifts are like x * 2 and x / 2, what is the real difference from actually using the * and / operators? Is there a performance difference?

bit-manipulation bitwise-operators bit-shift
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Some examples:

  • Bit operations for example converting to and from Base64 (which is 6 bits instead of 8)
  • doing power of 2 operations (1 << 4 equal to 2^4 i.e. 16)
  • Writing more readable code when working with bits. For example, defining constants using 1 << 4 or 1 << 5 is more readable.
answered 2011-06-17T12:37:01.333

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