Headache error message

okay, I keep getting this compiler error message:

Undefined. . . . . . . . . . . . . . . . . first referenced
symbol. . . .. . . . . . . . . . . . . . . . . . . in file
rob::Book::~Book() . . . . . . . . . . . /var/tmp//ccZWEnnc.o
rob::Book::Book() . . . . . . . . . . . . /var/tmp//ccZWEnnc.o
ld: fatal: Symbol referencing errors. No output written to a.out
collect 2: ld returned 1 exit status

rob::Book::~Book() <===this is the destructor for class Book in namespace rob that I created, the other one is the default constructor. I've tried everything I can think of and more. I need some serious help, I still have a lot left to work on for this project lol

Code:

---


//class header file
#include <string>
#include <cstdlib>

using namespace std;

namespace rob
{
  class Book
  {
    public:
      ~Book();
      Book (const Book& b1);
      void operator =(const Book& b1);
      Book();
      void print (ostream& outs);
      void fill (istream& ins);
    private:
      string* title;
      string* author;
      int copies, dollars, cents;
  };
}

//implementation file. I'll only put the destructor and default
//constructor because those are the problem ones

#include <iostream>
#include <cstdlib>
#include <string>
#include <fstream>
#include <cctype>
#include "book.h" //header file

using namespace std;
using namespace rob;

namespace rob
{
  Book::~Book()
  {
    delete title;
    delete author;
  }
  Book::Book()
  {
    title = new string;
    author = new string;
    copies = 0;
    dollars = 0;
    cents = 0;
    }
    //etc etc etc, the rest works fine
}

//main program, just testing to see if it compiles (which it doesn't)

#include "book.h"

using namespace std;
using namespace rob;

int main()
{
  Book b1;
  return 0;
}

---

if you see anything that could be wrong please help. I had it working fine as one file, but when I split it up it stopped working

I haven't compiled it, but I have a clue.

Code:

---

using namespace std;

namespace rob

---

By opening up the std namespace, I bet your rob namespace is inside it. Try the following driver program:

Code:

---

#include "book.h"

using namespace std;
using namespace rob;

int main()
{
  std::rob::Book b1;
  return 0;
}

---

edit: Actually, I have even less of a clue after I compiled it. I didn't get any linking errors.

I believe your problem is that you declared you were using a namespace before you defined it.

I don't think the problem is with the namespace. I defined namespace rob in the header file. I'm just adding the implementation to it in the other one. I don't get an error message with the other functions in my class, just with the default constructor and the destructor

Quote:

---

Originally Posted by Strait

okay, I keep getting this compiler error message:

Undefined. . . . . . . . . . . . . . . . . first referenced
symbol. . . .. . . . . . . . . . . . . . . . . . . in file
rob::Book::~Book() . . . . . . . . . . . /var/tmp//ccZWEnnc.o
rob::Book::Book() . . . . . . . . . . . . /var/tmp//ccZWEnnc.o
ld: fatal: Symbol referencing errors. No output written to a.out
collect 2: ld returned 1 exit status

rob::Book::~Book() <===this is the destructor for class Book in namespace rob that I created, the other one is the default constructor. I've tried everything I can think of and more. I need some serious help, I still have a lot left to work on for this project lol


if you see anything that could be wrong please help. I had it working fine as one file, but when I split it up it stopped working

---

How did you comple the program?

I put your header stuff in "book.h", the implementation stuff in "rob.cpp" and the main stuff in "main.cpp".

Then:

Quote:

---

g++ rob.cpp main.cpp -Wall -pedantic

---

No compiler messages.

Quote:

---

g++ main.cpp
...Temp/ccMICfav.o(.text+0x25):main.cpp: undefined reference to `rob::Book::Book[in-charge]()'
...Temp/ccMICfav.o(.text+0x30):main.cpp: undefined reference to `rob::Book::~Book [in-charge]()'
collect2: ld returned 1 exit status

---

Regards,

Dave

You have not compiled the implementation file. When you are compiling the main application file the linker is referencing object code that does not yet exist.

Compile (do not try to link) book.cpp first, then pass book.o to the linker when your compiling main.cpp.

HA! success. I just got rid of the pointers and the big 3. I misread the directions my professor gave me. I'm not supposed to use dynamic memory until the second part of this program lol.