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POClass Member Variable not Saving State
 

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    <p>I'm new to C/C++, so people excuse me if this is a noob question.</p> <p>I have a controller class, which has a private member variable which is a <code>vector&lt;Contact&gt; contacts</code>. The class has methods which allow us to change the state of this vector (standard CRUD operations).</p> <p>The class has a public method called <code>get_contacts()</code> which returns this private vector of objects:</p> <pre><code>std::vector&lt;Contact&gt; Contacts_Controller::get_contacts() const { return this-&gt;contacts; } </code></pre> <p>I have a method which adds the <code>contact</code> to this private vector via <code>push_back()</code>. The issue is that if the <code>add_contact()</code> method uses the accessor method, then the class variable does not get updated:</p> <pre><code>void Contacts_Controller::add_contact(const Contact &amp;contact) { this-&gt;get_contacts().push_back(contact); } </code></pre> <p>I <em>assume</em> this is a memory issue, perhaps I have some issues with my use of <code>const</code> or I'm not correctly using references, because the following code works exactly as expected:</p> <pre><code>void Contacts_Controller::add_contact(const Contact &amp;contact) { this-&gt;contacts.push_back(contact); } </code></pre> <p>Using either method won't return any errors, but if I then request the vector of contacts after using the first method it'll be empty, whereas the second method correctly adds data to the vector.</p> <p>Again, sorry if this is a noob question, but I'm completely stumped, and I wouldn't know what to search for! How would I fix this referencing issue?</p>
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    1. COYou are returning the vector by value in `get_contacts` so `push_back` is modifying a local copy that gets destroyed at the end of the statement.
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    2. COWhat exactly is C/C++?
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    3. CO@LightnessRacesinOrbit I am new to developing code in the C and C++ programming languages...
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