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    <p>You're mixing up pointers and references (which is understandable when you're comming from java/net). In C++, there is a clear distinction between:</p> <ol> <li><code>Cell x;</code>, an object (instance) of class <code>Cell</code></li> <li><code>Cell *x;</code>, a pointer to an instance of <code>Cell</code></li> <li><code>Cell &amp;x;</code>, a reference ("another name") to an instance of <code>Cell</code></li> </ol> <p>Java "references" are equivalent to C++ pointers.</p> <p>In your case, there are several issues. First, <code>setLeft()</code> needs to get the address of its argument, like this:</p> <pre><code>void setLeft(const Cell &amp; left) { this-&gt;left = &amp;left; } </code></pre> <p>Second, unless the class <code>Cell</code> is defined in a namespace <code>Cell</code>, the vector would have to be typed just <code>std::vector&lt;Cell&gt; cells;</code>.</p> <p>However, even more dangerous is the fact that your vector contains <em>statically</em> allocated <code>Cell</code> objects (its template argument is a class type, not a pointer). <code>std::vector</code> is allowed to move objects around in memory when it's added to, so once this happens, all existing pointers to objects stored in <code>cells</code> will become dangling. What you should do is store pointers in the vector instead:</p> <pre><code>std::vector&lt;Cell*&gt; cells; cells[pos]-&gt;setLeft(*cells[left]); //assuming setLeft() still takes a reference </code></pre> <p>It might actually be even better to use smart pointers (<code>std::shared_ptr</code> and <code>std::weak_ptr</code>) instead of raw pointers, but that's a separate topic.</p>
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    1. COOk thanks you helped me a lot. But I have one follow up questions. Do you have any idea why I am not able to acces the method of cells in the vector? `cells[0].setLeft(...);` setLeft is declared in the public block, but I am not able to get any access to a cell. Maybe because I am using a namespace?
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      1. USMaik Klein
    2. CO@MaikKlein How exactly are you "not able?"
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    3. COeclipse tells me that it is unable to resolve the method `setLeft` nor any of its public method/member variables.
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