undefined reference Error!

Would someone help me understand why I keep getting the error:
"In function main: [linker error] undefined reference to readBook(BookData)"

I have spend hours trying to fix it, but no luck :/

Thanks in advance

main.cpp :

Code:

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;
#include "BookData.h"

// FUNCTION PROTOTYPES:
void bookInfo(BookData);
void readBook(BookData& book1);

int main(){
    BookData book1, book2;
    cout << "\nEnter the data for the first book:\n";
    readBook(book1);
    cout << "\nEnter the data for the second book:\n";
    readBook(book2);
    cout << "\nDisplay the data for the first book:\n";
    bookInfo(book1);
    cout << "\nDisplay the data for the second book:\n";
    bookInfo(book2);
    system("pause");
    return 0;
}
void bookInfo(BookData book)
{
     string temp;
     cout << left;
     cout << "   " << setw(22) << "ISBN:" << book.getIsbn() << endl;
     cout << "   " << setw(22) << "Title:" << book.getTitle() << endl;
     cout << "   " << setw(22) << "Author:" << book.getAuthor() << endl;
     cout << "   " << setw(22) << "Publisher:" << book.getPub() << endl;
     cout << "   " << setw(22) << "Date Added:" << book.getDateAdded() << endl;
     cout << "   " << setw(22) << "Quantity-On-Hand:" << book.getQty() << endl;
     cout << "   " << setw(22) << "Wholesale Cost:" << "$" << fixed << setprecision(2) << book.getWholeSale() << endl;
     cout << "   " << setw(22) << "Retail Price:" << "$" << book.getRetail() << endl;
     temp = book.isEmpty()?"yes":"No";
     cout << "   " << setw(22) << "Empty?" << temp << endl;
}
void readBook(BookData& book1)
{
     string tempS;
     int tempI;
     double tempD;
     
     cout << "Enter the Title: ";
     cin >> tempS;
     book1.setTitle(tempS);        
     
     cout << "Enter the ISBN: ";
     cin >> tempS;
     book1.setIsbn(tempS);
     
     cout << "Enter the Author: ";
     cin >> tempS;
     book1.setAuthor(tempS);
     
     cout << "Enter the Publisher: ";
     cin >> tempS;
     book1.setPub(tempS);
     
     cout << "Enter Date Added: " ;
     cin >> tempS;
     book1.setDateAdded(tempS);
     
     cout << "Enter Quantity on Hand: ";
     cin >> tempI;
     book1.setQty(tempI);
     
     cout << "Enter Wholsale Price: " ;
     cin >> tempD;
     book1.setWholesale(tempD);
     
     cout << "Enter Retail Price: " ;
     cin >> tempD;
     book1.setRetail(tempD);
     
     cout << "Enter 1 to insert the book or 0 to remove: ";
     cin >> tempI;
     while (tempI > 1 || tempI < 0)
     {
           cout << "Wrong entry. Try again: ";
           cin >> tempI;
     }
     if (tempI == 0)
         book1.insertBook();
     else
         book1.removeBook();     
}

BookData.cpp :

Code:

#include <string>

class BookData
{
    private:
        string bookTitle;
        string isbn;
        string author;
        string publisher;
        string dateAdded;
        int qtyOnHand;
        double wholesale;
        double retail;
        bool empty;
        
    public:
        BookData();
        void setTitle(string object);
        void setIsbn(string code);
        void setAuthor(string auth);
        void setPub(string pub);
        void setDateAdded(string dateAdd);
        void setQty(int quant);
        void setWholesale(double price);
        void setRetail(double temp);
        bool isEmpty();
        void insertBook();
        void removeBook();
        string getTitle();
        string getIsbn();
        string getAuthor();
        string getPub();
        string getDateAdded();
        int getQty();
        double getWholeSale();
        double getRetail();
};

BookData::BookData()//Default Constructor
{
  qtyOnHand = 0;
  wholesale = 0;
  retail = 0;
  empty = true;
  bookTitle = isbn =  author =  publisher = dateAdded = "";
}

void BookData::setTitle(string object)
{
    bookTitle = object;
}

void BookData::setIsbn(string code)
{
    isbn = code;
}

void BookData::setAuthor(string auth)
{
    author = auth;
}

void BookData::setPub(string pub)
{
    publisher = pub;
}

void BookData::setDateAdded(string dateAdd)
{
    dateAdded = dateAdd;
}

void BookData::setQty(int quant)
{
    qtyOnHand = quant;
}

void BookData::setWholesale(double price)
{
    wholesale = price;
}

void BookData::setRetail(double temp){
       retail = temp;
}
bool BookData::isEmpty(){
     return empty;
}
void BookData::insertBook(){
     empty = false;
}
void BookData::removeBook(){
     empty = true;
}
string BookData::getTitle(){
       return bookTitle;
}
string BookData::getIsbn(){
    return isbn;
}
string BookData::getAuthor(){
       return author;
}
string BookData::getPub(){
        return publisher;
}
string BookData::getDateAdded(){
       return dateAdded;
}
int BookData::getQty(){
    return qtyOnHand;
}
double BookData::getWholeSale(){
       return wholesale;
}
double BookData::getRetail(){
       return retail;
}

DataBook.h :

Code:

#ifndef BOOKDATA_H
#define BOOKDATA_H
#include <string>

class BookData
{
    private:
        string bookTitle;
        string isbn;
        string author;
        string publisher;
        string dateAdded;
        int qtyOnHand;
        double wholesale;
        double retail;
        bool empty;
        
    public:
        BookData();
        void setTitle(string object);
        void setIsbn(string code);
        void setAuthor(string auth);
        void setPub(string pub);
        void setDateAdded(string dateAdd);
        void setQty(int quant);
        void setWholesale(double price);
        void setRetail(double temp);
        bool isEmpty();
        void insertBook();
        void removeBook();
        string getTitle();
        string getIsbn();
        string getAuthor();
        string getPub();
        string getDateAdded();
        int getQty();
        double getWholeSale();
        double getRetail();
};
#endif
        
        

 

I get no error (although I had to add "using namespace std;" to BookData.h) with Visual Studio 2010. What compiler and OS are you using (including version numbers)?

Also I would suggest not defining "class BookData" twice; just define it once in BookData.h, then #include BookData.h wherever you need it. Otherwise You will need to ensure both copies of class BookData remain consistent.

 

Yes. you are right. I was using the Dev C++, and had no idea I need to put them in a project to be able to run it! Thanks for the advice. I added the namespace, and erased the extra parts and it worked.