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    copied!<p>Change </p> <pre><code>std::vector&lt;Class2&gt; c2v; </code></pre> <p>to</p> <pre><code>std::vector&lt;Class2 *&gt; c2v; </code></pre> <p>and </p> <pre><code>std::vector&lt;Class3&gt; c3v; </code></pre> <p>to</p> <pre><code>std::vector&lt;Class3*&gt; c3v; </code></pre> <p>The problem is that you are taking adresses of local objects inside vector. When vector need more space it reallocates his memory and therefore <code>Class2</code> and <code>Class3</code> objects having their adresse changed.</p> <pre><code>class Class1 { public: std::vector&lt;Class2 *&gt; c2v; Class1(); }; class Class2 { Class1 *instance; int id; public: std::vector&lt;Class3 *&gt; c3v; Class2 ( Class1 *instance, int id ); }; class Class3 { Class1 *instance; int id; public: Class3 ( Class1 *instance, int id ); }; Class1::Class1() { for ( int i = 0; i &lt; noi; ++i ) { c2v.push_back ( new Class2 ( this, i ) ); } } Class2::Class2 ( Class1 *instance, int id ) { this-&gt;instance = instance; this-&gt;id = id; for ( int k = 0; k &lt; nok; ++k ) { c3v.push_back ( new Class3 ( this-&gt;instance, k ) ); } } </code></pre> <p>And don't forget to cleanup in Class1' and Class2' destructors.</p> <p>EDIT: Why such strange behaviour occured:</p> <p>Step 1</p> <pre><code>Ctqd::Ctqd() { for ( int i = 0; i &lt; nodes; ++i ) { suppliers.push_back ( Supplier ( this, i ) ); // &lt;-- Supplier's constructor is invoked here // to construct automatic object of Supplier class } } </code></pre> <p>Step 2. We are inside of the automatic object's constructor:</p> <pre><code>Supplier::Supplier ( Ctqd *instance, int id ) { for ( int k = 0; k &lt; numProdotti; ++k ) { offers.push_back ( Offer ( this, k ) ); // consider that we are passing this to // Offer's constructor. this is a pointer to // automatic variable } } </code></pre> <p>Step 3. Back to step 1. But now we have automatic object Supplier created</p> <pre><code>Ctqd::Ctqd() { for ( int i = 0; i &lt; nodes; ++i ) { suppliers.push_back ( Supplier ( this, i ) ); // &lt;-- automatic object of class Supplier // is created. Now as long as push_back() taking // parameter by value yo are passing copy of // automatic object to push_back(); // as long as you didn't define copy constructor // for Supplier compiler adds default for you. } } </code></pre> <p>Step 4. Copy of automatic object is saved to <code>suppliers</code> vector. New object (copy of automatic object) has vector <code>offers</code> with exactly same values as our automatic object had (thx to vector's copy constructor). So each object has member <code>supplier</code> that points to... (geass what :)) correct! they all point to automaic object.</p> <pre><code>Ctqd::Ctqd() { for ( int i = 0; i &lt; nodes; ++i ) { suppliers.push_back ( Supplier ( this, i ) ); // &lt;-- magic here } } </code></pre> <p>Step 5. Automatic object has been destructed(remember how you passed point to this object to Offer's constructor?). Oops you say.</p> <pre><code>Ctqd::Ctqd() { for ( int i = 0; i &lt; nodes; ++i ) { suppliers.push_back ( Supplier ( this, i ) ); // &lt;-- automatic doesn't exist no more } } </code></pre> <p>So what will happen if one of the supplier's methods gonna try to access <code>Supplier</code> object via <code>supplier</code> member (that we, smart kids, know points to dead object... so sad... QQ). Guess. I believe it will die by realising he sees dead object first time in his life ;).</p>
 

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