Thread: How do you do this one?

  1. 01-19-2008 #1
    Gwazi
    Gwazi is offline
    Registered User
    Join Date
    Jan 2008
    Posts
    11

    How do you do this one?

    !( ( 1 || 0 ) && 0 )
  2. 01-19-2008 #2
    laserlight
    laserlight is offline
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    Location
    Singapore
    Posts
    28,413
    Treat 1 as true and 0 as false, then evaluate the boolean expression.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
  3. 01-19-2008 #3
    Gwazi
    Gwazi is offline
    Registered User
    Join Date
    Jan 2008
    Posts
    11
    yeh thats what i need help with lol. im doing the tutorial on c++ i got the other two down but this last one is tricking me.
  4. 01-19-2008 #4
    Codeplug
    Codeplug is offline
    Registered User Codeplug's Avatar
    Join Date
    Mar 2003
    Posts
    4,981
    Which part is tricking you?

    gg
  5. 01-19-2008 #5
    Salem
    Salem is offline
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    Location
    The edge of the known universe
    Posts
    39,659
    Do what with it?
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
  6. 01-19-2008 #6
    Gwazi
    Gwazi is offline
    Registered User
    Join Date
    Jan 2008
    Posts
    11
    !( ( that part what do i do with the !
  7. 01-19-2008 #7
    laserlight
    laserlight is offline
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    Location
    Singapore
    Posts
    28,413
    The ! symbol means logical not.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
  8. 01-19-2008 #8
    Gwazi
    Gwazi is offline
    Registered User
    Join Date
    Jan 2008
    Posts
    11
    yes i know that much but im stuck figuring it out...can you just show me how you would go about doing it?
  9. 01-19-2008 #9
    laserlight
    laserlight is offline
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    Location
    Singapore
    Posts
    28,413
    Well, how would you evaluate (1 || 0)?
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
  10. 01-19-2008 #10
    Gwazi
    Gwazi is offline
    Registered User
    Join Date
    Jan 2008
    Posts
    11
    as 1
  11. 01-19-2008 #11
    laserlight
    laserlight is offline
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    Location
    Singapore
    Posts
    28,413
    So far so good. So how would you evaluate (1 && 0)?
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
  12. 01-19-2008 #12
    Gwazi
    Gwazi is offline
    Registered User
    Join Date
    Jan 2008
    Posts
    11
    as 0.
  13. 01-19-2008 #13
    laserlight
    laserlight is offline
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    Location
    Singapore
    Posts
    28,413
    Excellent. Just evaluate !0 and your problem is solved.

    EDIT:
    Strictly speaking, the result of (1 || 0) is true, not 1, and the result of (true && 0) is false, not 0.
    Last edited by laserlight; 01-19-2008 at 01:57 AM.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
  14. 01-19-2008 #14
    Gwazi
    Gwazi is offline
    Registered User
    Join Date
    Jan 2008
    Posts
    11
    See i just didnt know the order of it all. Thanks alot!
  15. 01-19-2008 #15
    laserlight
    laserlight is offline
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    Location
    Singapore
    Posts
    28,413
    No problem. Actually, with all those parentheses to group subexpressions the order of evaluation is no different from the arithmetic you used since elementary/primary school.

    More tricky would be:
    Code:
    !( 1 || 0 && 0 )
    ... which evaluates to false instead.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
« Previous Thread | Next Thread »
Popular pages Recent additions subscribe to a feed