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POAvoiding while (!is_eof)
 

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  1. POAvoiding while (!is_eof)
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    <p>I'm working with a (C++) library, where the object needs to be initialized with a stream. The sample code provided with the library uses this code:</p> <pre><code>// Declare the input stream HfstInputStream *in = NULL; try { // This sets up the special stream object for the later object (see below) in = new HfstInputStream("pathToFile.hfsto"); } // catch errors... // {omitted} // Initialize the object while (not in-&gt;is_eof()) { if (in-&gt;is_bad()) { std::cerr &lt;&lt; "ERROR: Stream cannot be read." &lt;&lt; std::endl; exit(1); } // Here we initialize the object using the stream HfstTransducer t(*in); } </code></pre> <p>My problem is that this object cannot be used outside of the while loop because of scoping. and I have to declare it with the stream (as far as I can tell), so I can't declare and then initialize it with the stream inside the loop.</p> <p>My questions are (1) am I wrong? Can I actually declare it outside the loop somehow? (2) is there another (better) way to do this that avoids the loop altogether. For example, if I were to use try/catch and catch the exceptions.</p> <p>I'm very new to C++ and looking to find out best practices, so please let me know what's what. Thanks.</p> <p>Also, to be clear, I'm looking to make a class that would use a persistant version of this object so I don't have to constantly create/destroy these objects every time I need to use them.</p> <p>PS: <a href="http://hfst.sourceforge.net/hfst3/classhfst_1_1HfstTransducer.html#a80b941c9d120fbec4596002c6a979096" rel="nofollow">here's a link to the documentation for the object if it is relevant</a></p> <p>EDIT: If I try to declare the variable outside the loop and then initialize it I get an error</p> <pre><code>HfstTransducer t; while (not in-&gt;is_eof()) { t(*in); } // ERROR: main.cpp:47:0 main.cpp:47: error: no match for call to '(hfst::HfstTransducer) (hfst::HfstInputStream&amp;)' </code></pre> <p>Am I trying to initialize it incorrectly?</p>
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    1. USdougalg
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    1. CO`HfstTransducer t(*in);` is in the loop scope. But `HfstInputStream *in` is not, you can access it outside the loop and use to initialize another `HfstTransducer` object or just use `HfstInputStream` pointer ... Unless, of course, `HfstTransducer` constructor has move semantics and erases `HfstInputStream *in`.
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      1. USlapk
    2. COIs your problem that you can't access t (which is an object of type HfstTranducer) outside of the loop? If so then you can just declare it outside of the loop on the heap and use the new operator to initialize it inside the loop. If not then I just misunderstood your problem :P
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      1. USLefteris
    3. COSorry if I wasn't clear. What I meant was that I would like to keep the HfstTransducer object around outside the loop and forget about the stream after the HfstTransducer been initialized instead of building a new HfstTransducer object every time. If that is even possible, it is my goal.
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      1. USdougalg
 

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