Link error ....redefinition of......

Link error ....redefinition of......

[Alex Luya]

I download source code for book <</Data Structures and Algorithm 
Analysis in C++ (Second Edition), /by Mark Allen Weiss>> 
from:http://users.cs.fiu.edu/~weiss/dsaa_c++/code/,try to compiler 
it,but got many errors,most of them say:
...... previously declared here
.......: redefinition of .....

I think template causes these errors,but how to fix it.
-----------------------------------------------------------------------
My configuration:
Ubuntu 9.04
GCC version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
Eclipse 3.4
CDT:.5.0.2
-------------------------------------------------------------------------

Files  and error message are following:

StackAr.h
-----
        #ifndef STACKAR_H
        #define STACKAR_H

        #include "../vector.h"
        #include "../dsexceptions.h"

        template <class Object>
        class Stack
        {
          public:
            explicit Stack( int capacity = 10 );
            bool isEmpty( ) const;
            .............
        #include "StackAr.cpp"
        #endif

--------------

StackAr.cpp

        #include "StackAr.h"
        template <class Object>
        Stack<Object>::Stack( int capacity ) : theArray( capacity )
        {
            topOfStack = -1;
        }

         template <class Object>
        bool Stack<Object>::isEmpty( ) const
        {
            return topOfStack == -1;
        }
...........

Test.cpp
#include <iostream>
#include "StackAr.h"
using namespace std;

int main()
{
    Stack<int> s;

    for (int i = 0; i < 10; i++)
        s.push(i);

    while (!s.isEmpty())
        cout << s.topAndPop() << endl;
    return 0;
}


---------------------------------------------
error message:

**** Build of configuration Debug for project DACPP ****

make all
Building file: ../src/stack/StackAr.cpp
Invoking: GCC C++ Compiler
g++ -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP 
-MF"src/stack/StackAr.d" -MT"src/stack/StackAr.d" 
-o"src/stack/StackAr.o" "../src/stack/StackAr.cpp"
../src/stack/StackAr.cpp:7: erreur: redefinition of 
‘Stack<Object>::Stack(int)’
../src/stack/StackAr.cpp:7: erreur: ‘Stack<Object>::Stack(int)’ 
previously declared here
../src/stack/StackAr.cpp:17: erreur: redefinition of ‘bool 
Stack<Object>::isEmpty() const’
../src/stack/StackAr.cpp:17: erreur: ‘bool Stack<Object>::isEmpty() 
const’ previously declared here
...............

Re: Link error ....redefinition of......

[Tim München]

On Tuesday 02 June 2009 08:16:35 Alex Luya wrote:
> I download source code for book <</Data Structures and Algorithm
> Analysis in C++ (Second Edition), /by Mark Allen Weiss>>
> from:http://users.cs.fiu.edu/~weiss/dsaa_c++/code/,try to compiler
> it,but got many errors,most of them say:
> ...... previously declared here
> .......: redefinition of .....
>
> I think template causes these errors,but how to fix it.


This is not the correct mailing list for such questions! Nevertheless, the 
reason for your compile errors is a simple one. Just drop the line

#include "StackAr.cpp"

from your header file. Why are you trying to include the implementation in the 
header? The other way round is how things work! (And you do have the header 
include in your implementation - why both directions?)



> -----------------------------------------------------------------------
> My configuration:
> Ubuntu 9.04
> GCC version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
> Eclipse 3.4
> CDT:.5.0.2
> -------------------------------------------------------------------------
>
> Files  and error message are following:
>
> StackAr.h
> -----
>         #ifndef STACKAR_H
>         #define STACKAR_H
>
>         #include "../vector.h"
>         #include "../dsexceptions.h"
>
>         template <class Object>
>         class Stack
>         {
>           public:
>             explicit Stack( int capacity = 10 );
>             bool isEmpty( ) const;
>             .............
>         #include "StackAr.cpp"
>         #endif
>
> --------------
>
> StackAr.cpp
>
>         #include "StackAr.h"
>         template <class Object>
>         Stack<Object>::Stack( int capacity ) : theArray( capacity )
>         {
>             topOfStack = -1;
>         }
>
>          template <class Object>
>         bool Stack<Object>::isEmpty( ) const
>         {
>             return topOfStack == -1;
>         }
> ...........
>
> Test.cpp
> #include <iostream>
> #include "StackAr.h"
> using namespace std;
>
> int main()
> {
>     Stack<int> s;
>
>     for (int i = 0; i < 10; i++)
>         s.push(i);
>
>     while (!s.isEmpty())
>         cout << s.topAndPop() << endl;
>     return 0;
> }
>
>
> ---------------------------------------------
> error message:
>
> **** Build of configuration Debug for project DACPP ****
>
> make all
> Building file: ../src/stack/StackAr.cpp
> Invoking: GCC C++ Compiler
> g++ -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP
> -MF"src/stack/StackAr.d" -MT"src/stack/StackAr.d"
> -o"src/stack/StackAr.o" "../src/stack/StackAr.cpp"
> ../src/stack/StackAr.cpp:7: erreur: redefinition of
> ‘Stack<Object>::Stack(int)’
> ../src/stack/StackAr.cpp:7: erreur: ‘Stack<Object>::Stack(int)’
> previously declared here
> ../src/stack/StackAr.cpp:17: erreur: redefinition of ‘bool
> Stack<Object>::isEmpty() const’
> ../src/stack/StackAr.cpp:17: erreur: ‘bool Stack<Object>::isEmpty()
> const’ previously declared here
> ...............



-- 
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<>                                                              <>
<> Tim München, M.Sc.        muenchen@physik.uni-wuppertal.de   <>
<> Bergische Universitaet                                       <>
<> FB C - Physik             Tel.: +49 (0)202 439-3521          <>
<> Gaussstr. 20              Fax : +49 (0)202 439-2811          <>
<> 42097 Wuppertal                                              <>
<>                                                              <>
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