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POC++: initialize reference to ofstream in initialization list
 

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  1. POC++: initialize reference to ofstream in initialization list
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    <p>I have read multiple questions and answers on that topic, but unfortunately none of them helped yet. I want to use the same debug file ouput in two classes A and B, where an instance of A creates an instance of B. I have something like:</p> <pre><code>class A { public: A() : debug("debug.txt") { }; private: std::ofstream debug; } class B { public: B(std::ofstream &amp;ofs) : debug(ofs) { }; private: std::ofstream &amp;debug; } </code></pre> <p>and create an instance of it with</p> <pre><code>B *b = new B(debugUnderlying); </code></pre> <p>which works quite well. However, I now want to have an additional constructor to be able to use it without an ofstream. The object shall then open a new file. I got the point that, as I have a reference, I need to initialize it in the initialization list. I tried multiple things:</p> <pre><code>B() : debug() { debug.open("debug2.txt"); }; error: invalid initialization of non-const reference of type ‘std::ofstream&amp; {aka std::basic_ofstream&lt;char&gt;&amp;}’ from an rvalue of type ‘const char*’ </code></pre> <p>or</p> <pre><code>B() : debug("debug2.txt") { }; error: value-initialization of reference type ‘std::ofstream&amp; {aka std::basic_ofstream&lt;char&gt;&amp;}’ </code></pre> <p>or (quite clear, since I have a temporary object)</p> <pre><code>error: invalid initialization of non-const reference of type ‘std::ofstream&amp; {aka std::basic_ofstream&lt;char&gt;&amp;}’ from an rvalue of type ‘std::ofstream {aka std::basic_ofstream&lt;char&gt;}’ </code></pre> <p>How can I do this? Thanks for any suggestions!</p>
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    1. CO`B *b = new B(debugUnderlying);` stop programming as in Java
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      1. USManu343726
    2. COCan you specify what you mean? As you may have guessed, this is not the original code.
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    3. COYou don't have any reason to dynamically-allocate the `B` instance.
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