Question about scope...

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  1. #1
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    Question about scope...

    Working through "Thinking in c++"... and yes I think I'm understanding it this time, thanks to everyone's help, the other day.

    One thing is not terribly clear...

    Code:
    void Fred (int x)
     { // a bunch of code
        if (x = 3)
          { Foo bar(31);    // class
           // calls to bar
          }                       <--- is bar destroyed here?
       // a bunch more code
      }                           <---or here?
    And ... can I do this to control bar's lifetime?

    Code:
    void Fred (int x)
     { // a bunch of code
       { Foo bar(31);    // class
         // calls to bar
       }                       
       // a bunch more code
      }

  2. #2
    and the hat of wrongness Salem's Avatar
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    The scope always ends at the matching closing brace of the opening brace containing the object in question.

    And yes, you can create scopes just by having open/close braces in the middle of the code. It's the syntactic equivalent of
    Code:
    void Fred (int x)
     { // a bunch of code
       if ( 1 ) { Foo bar(31);    // class
         // calls to bar
       }                       
       // a bunch more code
      }
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  3. #3
    -bleh-
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    Just for practicing purposes, you can write the destructor that print some message so that when your class goes out of scope you can see your class's destructor called.
    "All that we see or seem
    Is but a dream within a dream." - Poe

  4. #4
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    Thanks guys. Much appreciated.

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