🚀 go-pugleaf

Hello,

I am new to C++ and am trying to compile a sample program from Lippmans
book "C++ Primer", 2 ed. on page 63. I get the following compiler error:

p63.C: In function `int main()':
p63.C:27: type unification failed for function template `template <class Type>
void swap(Array<...> &, int, int)'	

This code compiles find on the Borland C++ compiler and the AIX xlC C++ 
compiler.

The problem seems to be with invoking a template function with a derived class.

I compiled like : g++ -o p63 pg3.C

The code (from Lippmans book) :

-------------Array.h-----------------------------
/*#################################################################
# Copyright (c) 1991 AT&T Bell Laboratories, All Rights Reserved   
# Published in ``A C++ Primer''  by Stanley Lippman, Addison-Wesley
#################################################################*/

#ifndef ARRAY_H
#define ARRAY_H

const int ArraySize = 12; 

template <class Type>
class Array {
public: 
    Array(int sz=ArraySize) 
        { size=sz; ia=new Type[ size ]; }
    virtual ~Array() { delete [] ia; }

    int getSize() { return size; }	
    virtual Type& 
        operator[](int index) { return ia[index]; }
protected: 
    int size;  
    Type *ia;
};

#endif
------------end Array.h-------------------

-------------Arr_RC.h---------------------------
/*#################################################################
# Copyright (c) 1991 AT&T Bell Laboratories, All Rights Reserved   
# Published in ``A C++ Primer''  by Stanley Lippman, Addison-Wesley
#################################################################*/

#ifndef ARRAYRC_H
#define ARRAYRC_H
#include <assert.h>
#include "Array.h"

template <class Type>
class ArrayRC : public Array<Type> {
public:
   ArrayRC(int sz = ArraySize) : Array<Type>( sz ){};
   Type& operator[](int index) { 
         assert( index >= 0 && index < size );
         return ia[ index ];
    }
};

#endif
------------end Arr_RC.h--------------------------

------------p63.C---------------------------
/*#################################################################
# Copyright (c) 1991 AT&T Bell Laboratories, All Rights Reserved   
# Published in ``A C++ Primer''  by Stanley Lippman, Addison-Wesley
#################################################################*/

#include <iostream.h>
#include "Array.h"
#include "Arr_RC.h"

template <class Type>
void swap( Array<Type> &array, int i, int j ) { 
     int tmp = array[ i ];
     array[ i ] = array[ j ];
     array[ j ] = tmp;
}

main() {
    Array<int> ia1;
    ArrayRC<int> ia2;

    cout << "swap() with IntArray<int> ia1\n";
    int size = ia1.getSize();
    swap( ia1, 1, size );

    cout << "swap() with IntArrayRC<int> ia2\n";
    size = ia2.getSize();
    swap( ia2, 1, size );

    return 0;
}
-----------end P63.C------------------------------
-----------------------------------------------------------------------
David Jones                  Tel: (607)751-3638
Loral Federal Systems        Fax: (607)751-3621
Route 17C  MD 0534           Email: dgj@lfs.loral.com
Owego, NY 13827
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