試圖實現通過引用傳遞給二叉樹使用的向量，我錯過了什麼？

Question

我正在嘗試編寫代碼以將二進制樹的inorder內容卸載到向量中。 IE：

#include <iostream> 
#include <vector> 
#include "BinaryTree.h" 
using namespace std; 

int main() 
{ 
    BinaryTree tree; 
    vector <double> v; 

    // Test iterative insert 
    cout << "Inserting the numbers 5 8 3 12 9."; 
    tree.insert(5); 
    tree.insert(8); 
    tree.insert(3); 
    tree.insert(12); 
    tree.insert(9); 


    // Test vectorExport() 
    tree.vectorExport(v); 
} 

我得到了一大堆錯誤的，因爲我不認爲我正確地實現它的成員函數做。我不知道我是否在錯誤的地方使用了&符號，或者它不在應該的位置。任何人的幫助，將不勝感激。
這是我收到的錯誤： [Error] prototype for 'void BinaryTree::vectorExport(BinaryTree::TreeNode*, std::vector<double>&)' does not match any in class 'BinaryTree'
這裏是我的類：

#ifndef DOUBLEBINARYTREE_H 
#define DOUBLEBINARYTREE_H 
#include <iostream> 
#include <vector> 
using namespace std; 
class BinaryTree 
{ 
private: 
    // The TreeNode class is used to build the tree. 
    class TreeNode 
    { 
     friend class BinaryTree; 
     double value; 
     TreeNode *left; 
     TreeNode *right; 
     TreeNode(double value1, TreeNode *left1 = NULL, 
          TreeNode *right1 = NULL) 
     { 
      value = value1; 
      left = left1; 
      right = right1; 
     }   
    }; 
    TreeNode *root;  // Pointer to the root of the tree 

    // Various helper member functions. 
    void insert(TreeNode *&, double); 
    bool search(TreeNode *, double); 
    void destroySubtree(TreeNode *); 
    void remove(TreeNode *&, double); 
    void makeDeletion(TreeNode *&); 
    void vectorExport(TreeNode *, vector<double>); 

public: 
    // These member functions are the public interface. 
    BinaryTree()  // Constructor 
     { root = NULL; } 
    ~BinaryTree()  // Destructor 
     { destroySubtree(root); } 
    void insert(double num) 
     { insert(root, num); } 
    bool search(double num) 
     { search(root, num); } 
    void remove(double num) 
     { remove(root, num);} 
    void vectorExport(vector<double> & v) 
     { vectorExport(root, v); } 

}; 

下面是實際的功能：

//********************************************************* 
// This function offloads tree contents to a vector  * 
//********************************************************* 
void BinaryTree::vectorExport(TreeNode *tree, vector<double> &v) 
{ 
    if (tree) 
    { 
     vectorExport(tree->left, vector<double> v); 
     v.push_back(tree->value); 
     vectorExport(tree->right, vector <double> v); 
    } 
} 

Answer 1

聲明參數作爲通過參考傳遞，例如

void vectorExport(TreeNode *, vector<double>&); 

不

void vectorExport(TreeNode *, vector<double>);