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POC++: reading data from an external file; problem with my code for stopping read before end of file
 

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  1. POC++: reading data from an external file; problem with my code for stopping read before end of file
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    <p>To use code I have written for performing calculations, I need to read in data (numbers and strings) from an external text file and store them in vectors of either strings or ints/doubles. I have written a template function for doing this. CashCow, Howard Hinnant, and wilhelmtell kindly helped with a previous problem. </p> <p>The function seems to work fine for ints/doubles, but I have a problem with string data.</p> <p>I need data from ONE line of my external file to go into a vector, but the function reads in multiple lines. Here's what I mean. Let's say this is what is in the external text file (below):</p> <hr> <p>vectorOne // Identifier for subset of data for one vector</p> <p>'1' '2' '3' // These values should go into one vector, (vectorOne)</p> <p>vectorTwo // Identifier for subset of data for another vector (vectorTwo)</p> <p>'4' '5' '6' // These values should go into a different vector</p> <p>vectorThree // Identifier for subset of data for another vector (vectorThree)</p> <p>'7' '8' '9' // These values should go into a different vector</p> <hr> <p>If I look for a data subset identifier/label (like vectorOne), I want only the data on the next line to go into my result vector. The problem is that ALL data below the identifier/label are ending up in the result vector. So if vectorTwo is what I want, I expect my result vector to contain the elements, "4, 5, 6." But intead, it contains 4 to 9. In my code (below), I thought that the line:</p> <pre><code>while ( file.get() != '\n' ); </code></pre> <p>ensured that the read would stop at a newline (i.e., after each line of data).</p> <p>I would be very grateful for any suggestions as to what is going wrong. </p> <p>Here's the code (for clarity, I configured it for strings):</p> <pre><code>#include &lt;algorithm&gt; #include &lt;cctype&gt; #include &lt;istream&gt; #include &lt;fstream&gt; #include &lt;iostream&gt; #include &lt;vector&gt; #include &lt;string&gt; #include &lt;sstream&gt; #include &lt;iterator&gt; using namespace std; template&lt;typename T&gt; void fileRead( std::vector&lt;T&gt;&amp; results, const std::string&amp; theFile, const std::string&amp; findMe, T&amp; temp ) { std::ifstream file( theFile.c_str() ); std::string line; while( std::getline( file, line ) ) { if( line == findMe ) { do{ std::getline( file, line, '\'' ); std::getline( file, line, '\''); std::istringstream myStream( line ); myStream &gt;&gt; temp; results.push_back( temp ); } while ( file.get() != '\n' ); } } } int main () { const std::string theFile = "test.txt"; // Path to file const std::string findMe = "labelInFile"; std::string temp; std::vector&lt;string&gt; results; fileRead&lt;std::string&gt;( results, theFile, findMe, temp ); cout &lt;&lt; "Result: \n"; std::copy(results.begin(), results.end(), std::ostream_iterator&lt;string&gt;(std::cout, "\n")); return 0; } </code></pre> <p>Thanks</p>
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