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POc++ vector problems
 

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  1. POc++ vector problems
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    <p>I am working with a <code>std::vector</code> to hold some objects that have dynamically allocated members, and when I go to put the Things into the vector a few things happen that I am not understanding.</p> <ol> <li><p>I call <code>push_back()</code> and use the constructor of the objects as the argument, but for some reason it goes to the destructor of the object. why is this; it should be adding not deleting?</p></li> <li><p>I call <code>push_back()</code> a second time doing the same as before, but this time it throws an illegal memory access at <code>dbgdel.cpp</code> operator delete (line 52). but delete should never be called in a constructor, or <code>push_back()</code>.</p></li> </ol> <p>I am uncertain what sections of code are pertinent to this question as the lines in question are pretty entrenched in a method. </p> <p>Edit: Code added</p> <pre><code>class Thing{ int** Array; int size; // of square array Point current; // location Thing(int _n){ // allocates, and gives values to the array, and members // only constructor } }; class ThingMgr{ Thing * Control; Thing * Current; Thing * Previous; int size; // size of all. same use as in Thing ThingMgr(int _n){ size = _n; Control = new Thing(size); Current = new Thing(size); Previous = new Thing(size); } void rearrange(int _num){ std::vector&lt;Thing&gt; possibles; // performs deterministic work on members // [0] first possibles.push_back(Thing(size)); // this succeeds // [1] second possibles.push_back(Thing(size)); // this fails // more operations to be performed never reached. } }; </code></pre>
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    1. USgardian06
    1. USgardian06
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    1. COCan you post the lines including the push_back(). I suspect that you are copying an object into the vector, and therefore an object is created, copied and then destructed (so the destructor is called)
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      1. POc++ vector problems
      1. USPaolo Brandoli
    2. COWhy don't you show the actual code? I'm not convinced that your prose description accurately matches your code as the jargon seems a bit .. unfixed
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      1. POc++ vector problems
      1. USsehe
    3. CODuring a `push_back` the vector class is allowed to make copies of your object using its copy constructor, and then some of those copies may be destroyed and their destructors will be called. Do you have a valid copy constructor for your class?
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      1. POc++ vector problems
      1. USBen Russell
 

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