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POtemplates: parent class member variables not visible in inherited class
 

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    <p>I have the following 4 files: </p> <ol> <li><code>arrayListType.h</code>: Declare and define <code>arrayListType</code> class as a template </li> <li><code>unorderedArrayListType.h</code>: Inherited from <code>arrayListType</code> class and Declares and defines <code>unorderedArrayListType</code> as a template. </li> <li><code>main1.cpp</code>: Test program to test <code>unorderedArrayListType</code> class. </li> <li><code>Makefile</code></li> </ol> <p>I get a compile error saying when accessing the protected variables of <code>arrayListType</code> in <code>unorderedArrayListType</code> for example: "length not declared in this scope", "list not declared in this scope", where length and list are protected variables in <code>arrayListType</code> class. </p> <p>The following are the codes:<br> arrayListType.h </p> <pre><code>#ifndef H_arrayListType #define H_arrayListType #include &lt;iostream&gt; using namespace std; template &lt;class elemType&gt; class arrayListType { public: const arrayListType&lt;elemType&gt;&amp;operator=(const arrayListType&lt;elemType&gt;&amp;); bool isEmpty() const; bool isFull() const; int listSize() const; int maxListSize() const; void print() const; bool isItemAtEqual(int location, const elemType&amp; item) const; virtual void insertAt(int location, const elemType&amp; insertItem) = 0; virtual void insertEnd(const elemType&amp; insertItem) = 0; void removeAt(int location); void retrieveAt(int location, elemType&amp; retItem) const; virtual void replaceAt(int location, const elemType&amp; repItem) = 0; void clearList(); virtual int seqSearch(const elemType&amp; searchItem) const; virtual void remove(const elemType&amp; removeItem) = 0; arrayListType(int size = 100); arrayListType(const arrayListType&lt;elemType&gt;&amp; otherList); virtual ~arrayListType(); protected: elemType *list; int length; int maxSize; }; template &lt;class elemType&gt; bool arrayListType&lt;elemType&gt;::isEmpty() const { return (length == 0); } // remaining non-virtual functions of arrayListType class #endif </code></pre> <p>unorderedArrayListType.h </p> <pre><code>#ifndef H_unorderedArrayListType #define H_unorderedArrayListType //#include &lt;iostream&gt; #include "arrayListType.h" //using namespace std; template &lt;class elemType&gt; class unorderedArrayListType: public arrayListType&lt;elemType&gt; { public: void insertAt(int location, const elemType&amp; insertItem); void insertEnd(const elemType&amp; insertItem); void replaceAt(int location, const elemType&amp; repItem); int seqSearch(const elemType&amp; searchItem) const; void remove(const elemType&amp; removeItem); unorderedArrayListType(int size = 100); }; template &lt;class elemType&gt; void unorderedArrayListType&lt;elemType&gt;::insertAt(int location, const elemType&amp; insertItem) { for(int i = length; i &gt; location; i--) list[i] = list[i - 1]; list[location] = insertItem; length++; } // Remaining virtual functions that need to be defined by the inherited class #endif </code></pre> <p>main1.cpp </p> <pre><code>#include &lt;iostream&gt; #include "unorderedArrayListType.h" using namespace std; int main() { unorderedArrayListType&lt;int&gt; intList(25); int number; cout&lt;&lt;"Line 3: Enter 8 integers: "; for(int count = 0; count &lt; 8; count++) { cin&gt;&gt;number; intList.insertEnd(number); } cout&lt;&lt;"Line 8: intList: "; intList.print(); cout&lt;&lt;endl; } </code></pre> <p>Makefile: </p> <pre><code>all: main1 main1.o: main1.cpp g++ -c -Wall main1.cpp main1: main1.o g++ -Wall main1.o -o main clean: rm -f *.o *~ main1 </code></pre> <p>The following is the compilation error: </p> <pre><code>make g++ -c -Wall main1.cpp In file included from main1.cpp:2: unorderedArrayListType.h: In member function 'void unorderedArrayListType&lt;elemType&gt;::insertAt(int, const elemType&amp;)': unorderedArrayListType.h:30: error: 'length' was not declared in this scope unorderedArrayListType.h:31: error: 'list' was not declared in this scope unorderedArrayListType.h:33: error: 'list' was not declared in this scope </code></pre> <p>More functions of <code>unorderedArrayListType</code> listed and protected variables indicated as not declared in the scope. Wondering what could be the error. </p> <p>New error: </p> <pre><code>make g++ -Wall main1.o -o main Undefined first referenced symbol in file arrayListType&lt;int&gt;::seqSearch(int const&amp;) constmain1.o ld: fatal: Symbol referencing errors. No output written to main collect2: ld returned 1 exit status *** Error code 1 make: Fatal error: Command failed for target `main1' </code></pre>
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