LNK2019 unresolved external symbol. Creating Binary Tree [duplicate] - c++

Question

This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 9 years ago.
I created Linked list and it has no problem and runs. Plus i have to include Binary Tree. and its giving me this error
1> Generating Code...
1> Skipping... (no relevant changes detected)
1> main.cpp
1>main.obj : error LNK2019: unresolved external symbol "public: int __thiscall SDI::BinaryTree::insert(int)" (?insert#BinaryTree#SDI##QAEHH#Z) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: int __thiscall SDI::BinaryTree::preOrder(void)" (?preOrder#BinaryTree#SDI##QAEHXZ) referenced in function _main
1>C:\Users\Muugii\Documents\Visual Studio 2013\LinkedList\Debug\LinkedList.exe : fatal error LNK1120: 2 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
BinaryTree.h
ifndef SDI_BINARYTREE
define SDI_BINARYTREE
include
namespace SDI
{
class BinaryTree
{
class BTNode
{
public:
int data;
BTNode *left;
BTNode *right;
};
public:
BinaryTree();
~BinaryTree();
int insert(const int value);
int preOrder() const;
int clearTree();
private:
BTNode *headPtr;
int insert(const int value, BTNode *leaf);
int clearTree(BTNode *leaf) const;
int preOrder(BTNode *leaf) const;
};
};
#endif
BinaryTree.cpp
#include"BinaryTree.h"
#include <iostream>
using namespace std;
SDI::BinaryTree::BinaryTree()
{
headPtr = nullptr;
}
SDI::BinaryTree::~BinaryTree()
{
//clearTree(headPtr);
}
int SDI::BinaryTree::insert(const int value, BTNode *leaf)
{
if (value < leaf->data)
{
if (leaf->left != nullptr)
{
insert(value, leaf->left);
}
else
{
leaf->left = new BTNode;
leaf->left->data = value;
leaf->left->left = nullptr;
leaf->left->right = nullptr;
}
}
else if (value >= leaf->data)
{
if (leaf->right != nullptr)
{
insert(value, leaf->right);
}
else
{
leaf->right = new BTNode;
leaf->right->data = value;
leaf->right->left = nullptr;
leaf->right->right = nullptr;
}
}
return 1;
}
Main.cpp
#include <string>
#include <iostream>
#include "Linkedlist.h"
#include "BinaryTree.h"
using namespace std;
int main( int argc, const char *argv[])
{
SDI::LinkedList myList;
//SDI::BinaryTree myTree;
int inp;
....
if (inp2 == 'a')
{
int num;
cout << "\nPlease enter a value to add: ";
cin >> num;
myTree.insert(num);
cout << "\n\t\tValue has been successfully saved\n\n\n";
}
I have tried looking up online, couldn't find any. It would be great help.

Answer 1

As I see you have two functions with name insert. And the first one
int insert(const int value);
was only declared but not defined.

Answer 2

Which part of the error message is unclear to you? It clearly states that you haven't implemented two of your methods:
int SDI::BinaryTree::insert(const int value) {
return 0; // the implementation probably needs some patching up
}
int SDI::BinaryTree::preOrder() const {
return 0; // as does this one
}