pointer's ->

This is a discussion on pointer's -> within the C++ Programming forums, part of the General Programming Boards category; Hi, all~ I read an article which said we could follow the format like this: Code: //assume we have a ...

  1. #1
    flashing vampire black's Avatar
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    pointer's ->

    Hi, all~

    I read an article which said we could follow the format like this:

    Code:
    //assume we have a class named myClass;
    class myClass
    {
      public:
        int value=0;
    };
    //and then our pointer comes;
    myClass *p;
    pointer->value=10;
    as known a pointer is variable stored address, how could it have a property here ???

    thanx for any explanation~
    Never end on learning~

  2. #2
    Skunkmeister Stoned_Coder's Avatar
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    Thats a segfault waiting to happen. you have a pointer but it points into random memory and not at an object.

    this is more correct....
    Code:
    myClass *p=new myClass;
    p->value=10; // ok now.
    delete p;
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  3. #3
    flashing vampire black's Avatar
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    Originally posted by Stoned_Coder
    Thats a segfault waiting to happen. you have a pointer but it points into random memory and not at an object.

    this is more correct....
    Code:
    myClass *p=new myClass;
    p->value=10; // ok now.
    delete p;
    sorry but I couldnt figure out what it should work for since not object at all...
    Never end on learning~

  4. #4
    flashing vampire black's Avatar
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    and I have no idea whether the dynamic allocation code always exists when we declare a pointer to class, yes or no ?
    Never end on learning~

  5. #5
    Guest Sebastiani's Avatar
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    myClass realObject;
    myClass *p;
    //p->value=10; //<--not yet! doesn't point to anything...
    p = &realObject;
    p->value=10; //...fine...

  6. #6
    flashing vampire black's Avatar
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    Originally posted by Sebastiani
    myClass realObject;
    myClass *p;
    //p->value=10; //<--not yet! doesn't point to anything...
    p = &realObject;
    p->value=10; //...fine...
    woh~ I got it ! dynamic allocation just assign some memory to our cute pointer when running, thanx !

    and... what about p.value ? it works fine but I couldnt imagine how a variable could have properties... I'm stuck here

    any ideas ?
    Never end on learning~

  7. #7
    flashing vampire black's Avatar
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    Originally posted by Salem
    > what about p.value
    No, following Sebastiani's example

    realObject.value = 10;
    p->value = 10;

    Do the same thing to the same object, but by different routes.
    sorry, I just mean p->value here. I am confused with a variable with contains properties, it's dizzy...
    Never end on learning~

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