Thread: ( t.hour < 10 ? "0" : "" ) << t.hour << ":" meaning.

  1. 05-14-2012 #1
    ncode
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    ( t.hour < 10 ? "0" : "" ) << t.hour << ":" meaning.

    Hi,
    I'm a new C++ user. I dont know what does this mean.

    Code:
    void printMilitary( const Time &t ) <---what does Time &t means?
{
   cout << ( t.hour < 10 ? "0" : "" ) << t.hour << ":"
        << ( t.minute < 10 ? "0" : "" ) << t.minute;
}
    ( t.hour < 10 ? "0" : "" ) a bit of weird to me. WHat does it mean?
  2. 05-14-2012 #2
    laserlight
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    if t.hour < 10, then the expression has the value of "0", otherwise it has the value of "".
    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. 05-14-2012 #3
    ncode
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    ok thanks, Then again. is const Time &t means - Type time of L-value of T which is a const?
  4. 05-14-2012 #4
    laserlight
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    It just means that t is a const reference parameter, i.e., of type const Time&.
    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
  5. 05-14-2012 #5
    ncode
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    Thanks again. Do you type wrong or something......type const Time&. Why & is at the back?
  6. 05-14-2012 #6
    GReaper
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    Quote Originally Posted by ncode View Post
    Thanks again. Do you type wrong or something......type const Time&. Why & is at the back?
    All together it's a constant reference. We usually pass structs by reference because they're big, but in case we try to accidentally alter them we add const.
    Devoted my life to programming...
  7. 05-14-2012 #7
    Elkvis
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    where the '&' goes is entirely up to you.

    Code:
    void printMilitary( const Time &t )
    is exactly the same as
    Code:
    void printMilitary( const Time& t )
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