already defined in ConsoleApplication1.obj,

Question

I have tried this solution but I am not able to understand it for my case.

My project Structure is

• ConsoleApplication1.cpp (main)
• BST.h
• BST.cpp
• help.cpp

Now my main is

#include "BST.h"
#include "help.cpp"

int main()
{
    BST b1;

    b1.insertion(5);
    b1.insertion(3);
    b1.insertion(2);
    b1.insertion(5);

    b1.insertion(7);
    b1.insertion(9);
    cout << predecessor(b1, 9)->data;

My BST.h is

#pragma once
#include <iostream>
using namespace std;
struct node {
    int data;
    node* leftchild, * rightchild, * parent;
};

class BST {
private:
    node* root;

public:
    BST();
    node* rooter();

    void insertion(int);
    void outleftandright();
    node* search(int x);

};

and BST.cpp is

#include "BST.h"

node* BST::search(int x)
{
    if (x == root->data)
    {
        return root;
    }
    node* temp = root;
    while (temp)
    {

        if (x < temp->data)
        {
            temp = temp->leftchild;
        }
        else if (x > temp->data)
        {
            temp = temp->rightchild;
        }
        else if (x == temp->data)
        {
            return temp;
        }
    }
}


void BST::outleftandright() {
    node* temp = root;
    cout << "LEFT\n";
    while (temp)
    {
        cout << temp->data << endl;
        temp = temp->leftchild;
    }
    temp = root;
    cout << "Right\n";
    while (temp)
    {
        cout << temp->data << endl;
        temp = temp->rightchild;
    }

}

BST::BST()
{
    root = nullptr;
}

node* BST::rooter()
{
    return root;
}

void BST::insertion(int data)
{
    if (root == nullptr)
    {
        root = new node;
        root->data = data;
        root->leftchild = nullptr;
        root->rightchild = nullptr;
    }
    else {
        node* temp = root;
        while (true)
        {

            if (data <= temp->data)
            {

                if (temp->leftchild == nullptr)
                {
                    temp->leftchild = new node;
                    temp->leftchild->parent = temp;
                    temp = temp->leftchild;

                    temp->data = data;
                    temp->leftchild = nullptr;
                    temp->rightchild = nullptr;
                    break;
                }
                temp = temp->leftchild;
            }
            else if (data > temp->data)
            {
                if (temp->rightchild == nullptr)
                {
                    temp->rightchild = new node;
                    temp->rightchild->parent = temp;
                    temp = temp->rightchild;
                    temp->data = data;
                    temp->leftchild = nullptr;
                    temp->rightchild = nullptr;
                    break;
                }
                temp = temp->rightchild;
            }
        }

        temp->data = data;
        temp->leftchild = nullptr;
        temp->rightchild = nullptr;
    }

}

and help.cpp is

#include "BST.h"

node* minimum(node* b1)
{
    while (b1->leftchild != nullptr)
    {
        b1 = b1->leftchild;
    }
    return b1;
}

node* maximum(node* temp)
{
    while (temp->rightchild != nullptr)
    {
        temp = temp->rightchild;
    }
    return temp;
}



node* successor(BST b1, int x)
{
    node* temproot = b1.search(x);
    node* temproot1 = temproot;
    if (temproot->rightchild != nullptr)
    {
        return minimum(temproot->rightchild);
    }
    else
    {
        node* y = temproot->parent;
        while (y != nullptr && temproot == y->rightchild)
        {
            temproot = y;
            y = temproot->parent;
        }
        if (y == nullptr)
        {
            return maximum(temproot1);
        }
        else {
            return y;
        }
    }
}

node* predecessor(BST b1, int x)
{
    node* temproot = b1.search(x);
    node* temproot1 = temproot;
    if (temproot->leftchild != nullptr)
    {
        return maximum(temproot->leftchild);
    }
    else
    {
        node* y = temproot->parent;
        while (y != nullptr && temproot == y->leftchild)
        {
            temproot = y;
            y = temproot->parent;
        }
        if (y == nullptr)
        {
            return minimum(temproot1);
        }
        else {
            return y;
        }
    }
}

Now When I did not had help.cpp and the functions inside help.cpp were in my Consol1Application1.cpp, it was working fine, but now it is giving error

1>help.obj : error LNK2005: "struct node * __cdecl maximum(struct node *)" (?maximum@@YAPEAUnode@@PEAU1@@Z) already defined in ConsoleApplication1.obj
1>help.obj : error LNK2005: "struct node * __cdecl minimum(struct node *)" (?minimum@@YAPEAUnode@@PEAU1@@Z) already defined in ConsoleApplication1.obj
1>help.obj : error LNK2005: "struct node * __cdecl predecessor(class BST,int)" (?predecessor@@YAPEAUnode@@VBST@@H@Z) already defined in ConsoleApplication1.obj
1>help.obj : error LNK2005: "struct node * __cdecl successor(class BST,int)" (?successor@@YAPEAUnode@@VBST@@H@Z) already defined in ConsoleApplication1.obj
1>C:\Users\Ahmad Mustafa Anis\source\repos\Week 13 Assign\ConsoleApplication1\x64\Debug\ConsoleApplication1.exe : fatal error LNK1169: one or more multiply defined symbols found

How to deal with it? Thanks

Answer 1

You shouldn't #include "help.cpp". That creates definitions of the functions in main.obj. When you then link that with help.obj (as you presumably are), you get duplicate definitions.

Instead, you should create help.h that contains just the function declarations from help.cpp. Then use

#include "help.h"

in the other files.

Answer 2

help.cpp wont work try renaming to help.h ho