what do these operations do?

This is a discussion on what do these operations do? within the C Programming forums, part of the General Programming Boards category; I am sorry if this is a stupid question but I have looked around and can not find the answer ...

  1. #1
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    what do these operations do?

    I am sorry if this is a stupid question but I have looked around and can not find the answer anywhere.

    What do these two operations do?

    a |= b

    and

    a=a>>1
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  2. #2
    ATH0 quzah's Avatar
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    Read the Bitwise Operation FAQ. All the information you need is already written up there.

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    Quote Originally Posted by the_head
    I am sorry if this is a stupid question but I have looked around and can not find the answer anywhere.

    What do these two operations do?

    a |= b

    and

    a=a>>1
    Those are bitwise operations. The first adds two variables or constants with bitwise OR, and the second shifts a value a certain number of bits. If you don't know how to read binary code, then they're rather useless to you.

    Say a=3 and b=5

    Code:
    //Not actually code, but whatever.
     0011
    +0101   //Add using bitwise OR
    =0111 //Our result is 7.
    And the second operation would shift A's bits over 1 place to the right.

    0011 >> 1 = 0001
    So 3>>1 = 1.
    Last edited by Krak; 01-29-2005 at 02:40 PM.

  4. #4
    & the hat of GPL slaying Thantos's Avatar
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    The first adds two variables or constants with bitwise OR
    Very poor choice of words here. OR is not addition, as such it doesn't "add" them together.

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    Quote Originally Posted by Thantos
    Very poor choice of words here. OR is not addition, as such it doesn't "add" them together.
    True..I kinda like to think of it as "adding with OR"...rather than calling it "OR'ing" them together, eh?

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