Thread: boolean operator "or"

  1. #1
    UpTooLate
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    Question boolean operator "or"

    Hi I am obviously new to c++. I can't figure out how you type in the boolean operator "or." Which keys is it on the keyboard???

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    Kernel hacker
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    Depends on your keyboard layout, which in turn depends on which "language" the keyboard is set up to use.

    You can get the same "character" by holding down ALT and typing 124 on the numeric part of the keyboard.

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    Officially An Architect brewbuck's Avatar
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    Quote Originally Posted by Amyaayaa View Post
    Hi I am obviously new to c++. I can't figure out how you type in the boolean operator "or." Which keys is it on the keyboard???
    The operator is ||. The character you are looking for is the vertical bar. I have used Russian, Hebrew, and US keyboards and on all of those, the symbol is on the same key as backslash. I don't know about other keyboards.

    Or, you can simply use the word "or" which means the same thing, in C++ only.

  4. #4
    and the hat of sweating
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    Use two pipe characters: ||
    On a standard US keyboard it's usually shift + '\' above the enter key.

    If your keyboard doesn't have a | key, you could always include <ciso646> and use "or" instead of "||".
    http://en.wikipedia.org/wiki/Iso646.h

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    Cat without Hat CornedBee's Avatar
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    On a German keyboard, you get the key using AltGr+<.
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    & the hat of GPL slaying Thantos's Avatar
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    Quote Originally Posted by cpjust View Post
    Use two pipe characters: ||
    On a standard US keyboard it's usually shift + '\' above the enter key.

    If your keyboard doesn't have a | key, you could always include <ciso646> and use "or" instead of "||".
    http://en.wikipedia.org/wiki/Iso646.h
    No need to include that file as it part of the C++ standard already.

  7. #7
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    Quote Originally Posted by Thantos View Post
    No need to include that file as it part of the C++ standard already.
    Then why would they bother having a <ciso646> for us to include to begin with?

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    C++ Witch laserlight's Avatar
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    Then why would they bother having a <ciso646> for us to include to begin with?
    I have no idea. The header seems completely redundant. A check of the MinGW port of g++ 3.4.5 reveals a <ciso646> header file that consists entirely of comments.
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  9. #9
    (?<!re)tired Mario F.'s Avatar
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    Well, those words are keywords already under the current C++ standard. The header is in fact part of the C95 standard that got added to C++ in 98 for reasons of consistency. There is indeed no need to add it under C++.
    Last edited by Mario F.; 02-15-2008 at 11:41 AM.
    Originally Posted by brewbuck:
    Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.

  10. #10
    UpTooLate
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    thank you, that is what I was looking for!

  11. #11
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    Quote Originally Posted by Mario F. View Post
    The header is in fact part of the C95 standard that got added to C++ in 98 for reasons of consistency.
    You mean C99?

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    Frequently Quite Prolix dwks's Avatar
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    Quote Originally Posted by cpjust View Post
    Use two pipe characters: ||
    On a standard US keyboard it's usually shift + '\' above the enter key.

    If your keyboard doesn't have a | key, you could always include <ciso646> and use "or" instead of "||".
    http://en.wikipedia.org/wiki/Iso646.h
    . . . or use trigraphs, though you'd probably have to enable them in your compiler options first.

    But don't use trigraphs unless you have to, because they can cause problems and look weird.

    [edit]
    > C95
    You mean C99?
    I was going to mention that too . . . C95 was what the standard used to be called when no one knew when the standard would actually finalize, AFAIK. It's generally called C99 now. [/edit]
    dwk

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  13. #13
    (?<!re)tired Mario F.'s Avatar
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    That's it then. Thanks for the correction. I had it edited from C99 to C95 when I saw the copyright on my header file. Didn't know C95 was just a moniker.
    Originally Posted by brewbuck:
    Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.

  14. #14
    Cat without Hat CornedBee's Avatar
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    Hmm ... isn't C95 like C++03, the date of a technical corrigendum?
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  15. #15
    (?<!re)tired Mario F.'s Avatar
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    It's possible yes because I do remember reading somewhere about iso646.h being added to the standard about that time - and not by C99 as the wikipedia article provided by cpjust reads.

    My memory is not to be trusted though. However, gcc iso646.h copyright is dated 1997

    EDIT: just confirmed with the cvs (old-gcc) and the file there is 12 years and 8 months old, dated June, 15 1995.
    Last edited by Mario F.; 02-15-2008 at 08:11 PM.
    Originally Posted by brewbuck:
    Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.

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