Re: undefined reference(compile error), plz help

From:

eric <cneric12lin0@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 9 Jun 2011 10:25:51 -0700 (PDT)

Message-ID:

<737d768d-cd8a-40c8-a5bc-28db4c852fc1@17g2000prr.googlegroups.com>

On Jun 9, 12:44 am, Paavo Helde <myfirstn...@osa.pri.ee> wrote:

eric <cneric12l...@gmail.com> wrote in news:33ca3f4e-bbef-4072-9fc6-
dec670fff...@x38g2000pri.googlegroups.com:

class IntArray {
public:
   // equality and inequality operations: #2b
   explicit IntArray( int size = DefaultArraySize );
   IntArray( int *array, int array_size );
   IntArray( const IntArray &rhs );

   // virtual destructor!
   virtual ~IntArray() { delete [] ia; }

   // equality and inequality operations:
   bool operator==( const IntArray& ) const;
   bool operator!=( const IntArray& ) const;

   // assignment operator: #2a
   IntArray& operator=( const IntArray& );
   int size() const { return _size; }

// we've removed the check on the index...
   virtual int& operator[](int index) { return ia[index]; }
   // int size() const; // #1
   virtual void sort(); // #4

[...]

but my compile result( errors) is
--
eric@eric-laptop:~/CppPrimer3$ g++ IntArray.cpp pg49.cpp
/tmp/ccOnEojJ.o: In function `IntArray::IntArray(int*, int)':
IntArray.cpp:(.text+0x8): undefined reference to `vtable for IntArray'

With g++ this typically means you have not provided definition of the
first non-inline virtual function in this class. As far as I can see,
this would be IntArray::Sort(). Provide a definition of this function
(and all other non-defined virtual functions) in the relevant .cpp file.

In C++ one can in principle leave out definitions for functions which are
not used, but all virtual functions are effectively "used" for populating
the vtable entries, so they must be all present in the program.

hth
Paavo

/
***************************************************************************=
********************/

Thanks Paavo and Brian your reply on this undefined reference

now I delete more variables, functions in my IntArray.h and add
IntArrayRC.cpp(and IntArray.cpp)
/
***************************************************************************=
********************/
#ifndef IntArray_H
#define IntArray_H

class IntArray {
public:
   // equality and inequality operations: #2b
   explicit IntArray( int size = DefaultArraySize );
   IntArray( int *array, int array_size );
   IntArray( const IntArray &rhs );

   // virtual destructor!
   // virtual ~IntArray() { delete [] ia; }

   // equality and inequality operations:
   bool operator==( const IntArray& ) const;
   bool operator!=( const IntArray& ) const;

   // assignment operator: #2a
   IntArray& operator=( const IntArray& );
   int size() const { return _size; }

// we've removed the check on the index...
   /* virtual */ int& operator[](int index) { return ia[index]; }
   // int size() const; // #1
// virtual void sort(); // #4

   //virtual int min() const; // #3a
   //virtual int max() const; // #3b

   // if the value is found within the aray,
   // return the index of its first occurrence
   // otherwise, return -1

   /*virtual*/ int find ( int value ) const; // #3c

  protected:
    // the private implementation
    static const int DefaultArraySize = 12;
    void init( int sz, int *array );

    int _size;
    int *ia;
};

#endif
/*--------------------*/
#ifndef IntArrayRC_H
#define IntArrayRC_H

#include "IntArray.h"

class IntArrayRC : public IntArray {
public:
  IntArrayRC( int _size = DefaultArraySize );
  IntArrayRC( int *array, int array_size );
  IntArrayRC( const IntArrayRC &rhs );
/* virtual*/ int& operator[]( int );

private:
  void check_range( int );
};

#endif
/*----------------------------*/
// IntArrayRC.cpp

#include "IntArrayRC.h"

IntArrayRC::IntArrayRC(int *iarray, int iarray_size)
{
  ia = iarray;
  _size = iarray_size;
}
/*-------------------------------------------------------*/
// IntArray.cpp

#include "IntArray.h"

IntArray::IntArray(int *iarray, int iarray_size)
{
  ia = iarray;
  _size = iarray_size;
}

/*-------------------------------------------------------*/
/* my pg49.cpp and IntArray.cpp didn't change */
/*--------- ----------*/
/* I tried to make everything simple, just hope to make it run, but
it still not work, and I don't see my IntArrayRC.cpp or pg49.cpp
reference
* IntArray::IntArray(int)' at all. how come compiler complain
that?
*/
eric@eric-laptop:~/CppPrimer3$ g++ IntArray.cpp IntArrayRC.cpp
pg49.cpp
/tmp/ccFlMagZ.o: In function `IntArrayRC::IntArrayRC(int*, int)':
IntArrayRC.cpp:(.text+0x15): undefined reference to
`IntArray::IntArray(int)'
collect2: ld returned 1 exit status
eric@eric-laptop:~/CppPrimer3$

looking to see any advancer's help again, and
Thanks a lot in advance,
Eric