[Consulta] Arboles binarios

[Gunhack]

Buenas a quien lo lea!

Estoy programando un árbol binario, pero al momento de compilar el programa, la función virtual no la reconoce o no se linkea, ¿a qué se debe? o que hago mal?   ojalá puedan ayudarme, gracias!

BTNode.h :

Código (cpp) [Seleccionar] Expandir


#define BTNODE_H_INCLUDED

#include <sstream>

using namespace std;

template<typename IT>
struct BTNode {

 IT data;
 BTNode<IT>* left;
 BTNode<IT>* right;

 BTNode(const IT &Data, BTNode<IT>* lv = NULL, BTNode<IT>* rv = NULL) :
   data(Data), left(lv), right(rv) {}

 virtual ~BTNode() {}

 virtual string toString() const {

   ostringstream os;

   os << data;
   return os.str();
 }
};

template <typename IT>
ostream &operator<<(ostream &out, const BTNode<IT> &node) {

 return out << node.toString();
}

#endif // BTNODE_H_INCLUDED




Binary_Tree.h:

Código (cpp) [Seleccionar] Expandir



#ifndef BINARY_TREE_H_INCLUDED
#define BINARY_TREE_H_INCLUDED

#include <cstddef>
#include <sstream>
#include <stdexcept>
#include <string>
#include "BTNode.h"

using namespace std;

template <typename IT>
class Binary_Tree {

public:

 Binary_Tree(): root(NULL) {}
 Binary_Tree(const IT &Data, const Binary_Tree<IT> &lc = Binary_Tree(), const Binary_Tree<IT> &rc = Binary_Tree()):
   root(new BTNode<IT>(Data, lc.root, rc.root)) {}

 virtual ~Binary_Tree() {}

 Binary_Tree<IT> getLeftSubtree() const;
 Binary_Tree<IT> getRigthSubtree() const;
 const IT &getData() const;

 bool isNull() const;
 bool isLeaf() const;

 virtual string toString() const; //<---esta es la función!!!!

 static Binary_Tree<IT> readBinaryTree(istream& in);
Binary_Tree(BTNode<IT>* newRoot): root(newRoot) {}
protected:


 BTNode<IT>* root;
};

template<typename IT>
ostream &operator<<(ostream &out, const Binary_Tree<IT> &tree) {

 return out << tree.toString();
}

template<typename IT>
istream &operator>>(istream &in, Binary_Tree<IT> &tree) {

 tree = Binary_Tree<IT>::readBinaryTree(in);
 return in;
}

#endif // BINARY_TREE_H_INCLUDED



Binary_Tree.cpp

Código (cpp) [Seleccionar] Expandir


#include "Binary_Tree.h"

using namespace std;

template<typename IT>
Binary_Tree<IT> Binary_Tree<IT>::getLeftSubtree() const {

 if(root == NULL) {

   throw invalid_argument("getLeftSubtree on empty tree");
 }

 return Binary_Tree<IT>(root->left);
}

template<typename IT>
Binary_Tree<IT> Binary_Tree<IT>::getRigthSubtree() const {

 if(root == NULL) {

   throw invalid_argument("getLeftSubtree on empty tree");
 }

 return Binary_Tree<IT>(root->right);
}

template<typename IT>
bool Binary_Tree<IT>::isLeaf() const {

 if(root != NULL) {

   return root->left == NULL && root->right == NULL;
 } else {

   return true;
 }
}

template<typename IT>
string Binary_Tree<IT>::toString() const {

 ostringstream os;

 if(isNull()) {

   os << "NULL\n";
 } else {

   os << *root << "\n";
   os << getLeftSubtree().toString();
   os << getRigthSubtree().toString();
 }

 return os.str();
}



[ivancea96]

En primer lugar, coloca el error.

Luego, ¿Por qué métodos virtuales? ¿Funciona correctamente sin ser virtual?