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Problem matching Function Signitures with const

Posted on 2004-10-29
Medium Priority
Last Modified: 2008-02-01
Hello Experts,

I have what shold be a fairly easy 500 pts for someone.  I just cant seem to get my function signitures to match correctly in a Tree class that I am making.

My problem is this;

I have a public member function:                

                           int leafcount() const;                      <---  this must be the signiture because it is a requirement of the teacher.

in the function body I place a call to this funciton private member function:

                           void leafcount(const TreeNode*&, int&) const;  

And when I compile I get these errors:

                           BTree.cpp:                  In member function `int BTree::leafcount() const':
                           BTree.cpp:184:            no matching function for call to `BTree::leafcount(TreeNode*const&, int&) const'
                           BTree.cpp:182:            candidates are: int BTree::leafcount() const
                           BTree.h:47:                 void BTree::leafcount(const TreeNode*&, int&) const
                           BTree.cpp:                   In member function `void BTree::leafcount(const TreeNode*&, int&) const':
                           BTree.cpp:                   193: no matching function for call to `BTree::leafcount(TreeNode*const&, int&) const'
                           BTree.cpp:182:             candidates are: int BTree::leafcount() const
                           BTree.cpp:189:             void BTree::leafcount(const TreeNode*&, int&) const
                           BTree.cpp:195:             no matching function for call to `BTree::leafcount(TreeNode*const&, int&) const'
                           BTree.cpp:182:             candidates are: int BTree::leafcount() const
                           BTree.cpp:189:             void BTree::leafcount(const TreeNode*&, int&) const

Now, I can fix all my problems if I simply change my function calls...

                           int leafcount() const;     &     void leafcount(const TreeNode*&, int&) const;  


                            int leafcount()             &      void leafcount(TreeNode*&, int&);

but as I said, I need the const...  So thats it!.. To help you help me, below is my BTree class header file and the implementation of both functions.


//BTree.h fiel

#include <cstdlib>
#include "TreeNode.h"

using namespace std;

#ifndef BTREE_H
#define BTREE_H

class BTree
      //int findkey(const int& key) const;//
      //int findmax(const int& key) const;//

      BTree(const BTree& atree);
      bool insert(const int& d);
      int findheight();
      void RecursiveInOrder(void(*visit)(int& i));
                void NonRecursivePostOrder(void (*visit)(int& i));
      void NonRecursiveLevelOrder(void(*visit)(int& i));
      int nodecount() const;
      int leafcount() const;            
      int countfullnodes();


                //void leafcout(const TreeNode*&, int&);//
      TreeNode *root;
      bool insert(TreeNode*&, const int&);
      bool copyTree(TreeNode* treePtr, TreeNode*& newTreePtr);
      int findheight(TreeNode*);
      void RecursiveInOrder(TreeNode*, void(*visit)(int& i));
      void leafcount(const TreeNode*&, int&) const;
      int totalnodes;
      void countfullnodes(TreeNode*&, int&);




//Implementation of functions:

int BTree::leafcount() const
      int count = 0;
      leafcount(root, count);
      return count;

void BTree::leafcount(const TreeNode*& parent, int& count) const
            if(parent->left != NULL)
                  leafcount(parent->left, count);
            if(parent->right != NULL)
                  leafcount(parent->right, count);
                  count = count + 1;



Question by:travishaberman
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Accepted Solution

georg74 earned 2000 total points
ID: 12448484

> void leafcount(const TreeNode*&, int&) const;  

you wanted to pass reference to a const pointer to the function.
this is not necessary. chnage it to simply pass the pointer.

void leafcount(const TreeNode *, int &) const;

that's all. the way you're calling it is correct.

if you want to do it in more elegant way, (but still as recursive function,)
don't pass int & for count, but return the count as the result of the function:

unsigned leafcount(const TreeNode *node) const
    if (node == 0) return 0;
    return 1 + leafcount(node->left) + leafcount(node->right);

have fun,

Author Comment

ID: 12454056
Thank you much George!

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