virtual function

[shenakan]

I tried to compile a class with virtual functions and qtcreator want only compile the functions inside the header. I cannot compîle when the functions are in the cpp file. The compilator says the vtable is not defined.

[nish]

can you show some code?

[shenakan]

#ifndef PATH_H
#define PATH_H
 
#include <fstream>
#include <iostream>
#include <sstream>
#include <iomanip>
 
using namespace std;
 
class Path{
 protected:
 
 public:  
  virtual double getOrientation() const;
};
 
#ifndef TRANSIT_H
#define TRANSIT_H
 
 
#include <iomanip>
#include <fstream>
#include <iostream>
#include <string.h>
#include "path.h"
 
 
using namespace std;
 
class Transit : public Path{
 
 public:
  Transit(const char *info);
 
  double getOrientation() const;
};
#endif

#ifndef PATH_H
#define PATH_H

#include <fstream>
#include <iostream>
#include <sstream>
#include <iomanip>

using namespace std;

class Path{
 protected:
 
 public:  
  virtual double getOrientation() const;
};

#ifndef TRANSIT_H
#define TRANSIT_H


#include <iomanip>
#include <fstream>
#include <iostream>
#include <string.h>
#include "path.h"


using namespace std;

class Transit : public Path{
  
 public:
  Transit(const char *info);
 
  double getOrientation() const;
};
#endif

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I get this message : undefined reference to "vtable for Path"

[shenakan]

ok I found my problem. I forgot to add =0 at the end of my virtual function and also a const in one of function of the derivated class.

virtual double getOrientation() const = 0;

virtual double getOrientation() const = 0;

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[nish]

the defination looks alrite to me.... are you defining function in both the classes?
EDIT: - too late

[Baltimore]

If you don't want the "getOrientation()" method to be virtual pure ( = 0 ), you could also define a virtual destructor for the Path class.