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POCompile errors while read/write size of multiple structs to file
 

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  1. POCompile errors while read/write size of multiple structs to file
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    <p>I've already asked 2 questions kind of related to this project, and i've reached this conclusion. Writing the size of the Struct to the file , and then reading it back is the best way to do this.</p> <p>I'm creating a program for a homework assignment that will allow me to maintain inventory. I need to read / write multiple structs of the same type to a file.</p> <p>The problem is... this is really complicated and i'm having trouble wrapping my head around the whole process. I've seen a bunch of examples and i'm trying to put it all together. I'm getting compile errors... and I have zero clue on how to fix them. If you could help me on this I would be so appreciative... thank you. I'm so lost right now... </p> <p>**** HOPEFULLY THE LAST EDIT #3 *************</p> <p>My Code:</p> <pre><code>// Project 5.cpp : main project file. #include "stdafx.h" #include &lt;iostream&gt; #include &lt;fstream&gt; #include &lt;string&gt; #include &lt;vector&gt; #include &lt;algorithm&gt; using namespace System; using namespace std; #pragma hdrstop int checkCommand (string line); template&lt;typename Template&gt; void readFromFile(Template&amp;); template&lt;typename Template&gt; void writeToFile(Template&amp;); template&lt;typename T&gt; void writeVector(ofstream &amp;out, const vector&lt;T&gt; &amp;vec); template&lt;typename Template&gt; void readVector(ifstream&amp; in, vector&lt;Template&gt;&amp; vec); struct InventoryItem { string Item; string Description; int Quantity; int wholesaleCost; int retailCost; int dateAdded; } ; int main(void) { cout &lt;&lt; "Welcome to the Inventory Manager extreme! [Version 1.0]" &lt;&lt; endl; vector&lt;InventoryItem&gt; structList; ofstream out("data.dat"); writeVector( out, structList ); while (1) { string line = ""; cout &lt;&lt; endl; cout &lt;&lt; "Commands: " &lt;&lt; endl; cout &lt;&lt; "1: Add a new record " &lt;&lt; endl; cout &lt;&lt; "2: Display a record " &lt;&lt; endl; cout &lt;&lt; "3: Edit a current record " &lt;&lt; endl; cout &lt;&lt; "4: Exit the program " &lt;&lt; endl; cout &lt;&lt; endl; cout &lt;&lt; "Enter a command 1-4: "; getline(cin , line); int rValue = checkCommand(line); if (rValue == 1) { cout &lt;&lt; "You've entered a invalid command! Try Again." &lt;&lt; endl; } else if (rValue == 2){ cout &lt;&lt; "Error calling command!" &lt;&lt; endl; } else if (!rValue) { break; } } system("pause"); return 0; } int checkCommand (string line) { int intReturn = atoi(line.c_str()); int status = 3; switch (intReturn) { case 1: break; case 2: break; case 3: break; case 4: status = 0; break; default: status = 1; break; } return status; } template &lt;typename Template&gt; void readFromFile(Template&amp; t) { ifstream in("data.dat"); readVector(in, t); Need to figure out how to pass the vector structList via a Template in.close(); } template &lt;typename Template&gt; void writeToFile(Template&amp; t) { ofstream out("data.dat"); readVector(out, t); Need to figure out how to pass the vector structList via a Template out.close(); } template&lt;typename T&gt; void writeVector(ofstream &amp;out, const vector&lt;T&gt; &amp;vec) { out &lt;&lt; vec.size(); for(vector&lt;T&gt;::const_iterator i = vec.begin(); i != vec.end(); ++i) { out &lt;&lt; *i; // SUPER long compile error } } template&lt;typename T&gt; vector&lt;T&gt; readVector(ifstream &amp;in) { size_t size; in &gt;&gt; size; vector&lt;T&gt; vec; vec.reserve(size); for(int i = 0; i &lt; size; ++i) { T tmp; in &gt;&gt; tmp; vec.push_back(tmp); } return vec; } </code></pre> <p>My Compile Errors:</p> <pre><code>1&gt;.\Project 5.cpp(128) : error C2679: binary '&lt;&lt;' : no operator found which takes a right-hand operand of type 'const InventoryItem' (or there is no acceptable conversion) 1&gt; C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\include\ostream(653): could be 'std::basic_ostream&lt;_Elem,_Traits&gt; &amp;std::operator &lt;&lt;&lt;char,std::char_traits&lt;char&gt;&gt;(std::basic_ostream&lt;_Elem,_Traits&gt; &amp;,const char *)' 1&gt; with </code></pre> <p>That is the only error i'm getting now. I see your code is SO Much better. My new compiler error is SUPER long. I've shown where it the error points to. Could you help me just one last time?</p>
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    1. COI think it would be better if modifications to the original code are posted as answers/follow-ups rather than modifying the question. At the end, the original answers will be completely offset and will be confusing for other readers
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      1. USDavid Rodríguez - dribeas
 

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