Thread: Chapter 21 Help

Hi,

I am getting a build error when I break the code in the book down to a .h file and 2 .cpp files and I'm not sure why. I am following the steps in the book fairly accurately I think. I run the program through orig.cpp and I get the following build error.

mingw32-g++.exe -c X:\Users\Notneeded\jumpcplusplus\orig.cpp -o X:\Users\Notneeded\jumpcplusplus\orig.o

mingw32-g++.exe -o
X:\Users\Notneeded\jumpcplusplus\orig.exe X:\Users\DSoutherland\jumpcplusplus\orig.o

X:\Users\Notneeded\jumpcplusplus\orig.orig.cpp.text+0x91): undefined reference to `addNode(Node*, int)'

X:\Users\Notneeded\jumpcplusplus\orig.orig.cpp.text+0xb4): undefined reference to `printList(Node const*)'

collect2.exe: error: ld returned 1 exit status


I thought by #include "linkedlist.h" in the orig.ccp code it would allow communication between the linkedlist.h and the linkedlist.cpp but it doesn't appear that the orig.cpp file has access to the logic of the functions.

Wondering what I am missing?

(s), 0 warning(s) (0 minute(s), 1 second(s))
linkedlist.h

Code:

Code:

struct Node
{
    Node *p_next;
    int value;
};Node *addNode (Node* p_list, int value);
void printList (const Node* p_list);

linkedlist.cpp

Code:

#include <iostream>
#include "linkedlist.h"
using namespace std;
Node *addNode (Node* p_list, int value)
{
    Node *p_new_node = new Node;
    p_new_node->value = value;
    p_new_node->p_next = p_list;
    return p_new_node;
}
void printList (const Node* p_list)
{
    const Node* p_cur_node = p_list;
    while (p_cur_node != NULL)
    {
        cout << p_cur_node->value << endl;
        p_cur_node = p_cur_node->p_next;
    }
}

orig.cpp

Code:

Code:

#include <iostream>
#include "linkedlist.h"
using namespace std;
int main ()
{
    Node *p_list = NULL;
    for ( int i = 0; i<10; ++i)
    {
        int value;
        cout << "Enter value for list node: ";
        cin >> value;
        p_list = addNode(p_list, value);
    }
    printList(p_list);
}

It appears that you need to add linkedlist.cpp to your build line.

Jim

Hi Jim,

In orig.cpp I've replaced #include "linkedlist.h" with #include "linkedlist.cpp" and the program works. I don't know if you are familiar with the book but it says never include a .cpp file directly due to the compiler seeing multiple definitions of the same function. I'm having trouble visualizing that statement and whether or not I am taking a bad shortcut?

Thanks,

Dave

Thanks all.