C++ Interface Compiling - c++

Question

EDIT:
I figured out the solution. I was not adding -combine to my compile instructions and that was generating the errors.
I'm in the process of working through the Deitel and Deitel book C++ How to Program and have hit a problem with building and compiling a C++ interface using g++. The problem is, I've declared the class in the .h file and defined the implementation in the .cpp file but I can't figure out how to get it to compile and work when I try to compile the test file I wrote. The g++ error I'm receiving is:
Undefined symbols:
"GradeBook::GradeBook(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)", referenced from:
_main in ccohy7fS.o
_main in ccohy7fS.o
"GradeBook::getCourseName()", referenced from:
_main in ccohy7fS.o
_main in ccohy7fS.o
ld: symbol(s) not found
collect2: ld returned 1 exit status<
If someone could point me in the right direction I'd be appreciative.
My header file:
//Gradebook 6 Header
//Purpose is to be the class declaration for the class Gradebook 6
//Declare public, privates, and function names.
#include //the standard c++ string class library
using std::string;
//define the class gradebook
class GradeBook
{
public: //all the public functions in the class
GradeBook(string ); //constructor expects string input
void setCourseName (string ); //method sets course name--needs string input
string getCourseName(); //function returns a string value
void displayMessage(); //to console
private: //all private members of the class
string courseName;
}; //ends the class declaration
My .cpp file is:
//Gradebook 6
// The actual implementation of the class delcaration in gradebook6.h
#include
using std::cout;
using std::endl;
#include "gradebook6.h" //include the class definition
//define the class gradebook
GradeBook::GradeBook(string name) //constructor expects string input
{
setCourseName(name); //call the set method and pass the input from the constructor.
}
void GradeBook::setCourseName (string name) //method sets course name--needs string input
{
courseName = name; //sets the private variable courseName to the value passed by name
}
string GradeBook::getCourseName() //function returns a string value
{
return courseName;
}
void GradeBook::displayMessage() //function does not return anything but displays //message to console
{
cout //message here, the pre tag isn't letting it display
} //end function displayMessage
Finally, the test file I wrote to implement the interface and test it.
// Gradebook6 Test
// Program's purpose is to test our GradeBook5 header file and file seperated classes
#include
using std::cout;
using std::endl;
#include "gradebook6.h" //including our gradebook header from the local file.
//being program
int main()
{
//create two gradebook objects
GradeBook myGradeBook1 ("CSC 101 Intro to C++ Programming"); //create a default object using the default constructor
GradeBook myGradeBook2 ("CSC 102 Data Structures in C++");
//display intitial course name
cout //another output message here that the code tag does not like
return 0;
}

Answer 1

Looks like you just need to link in the GradeBook.cpp object file to your final executable. Care to post your makefile or the way you are building it?

Answer 2

What you are seeing are linker errors (the indication is in the "ld returned" bit: ld is the linker). You need to either give all the .cpp files to g++, so it will compile and link them, or use the latter's -c switch to make a .o from the .cpp and then use THAT .o on a further g++ command to build (link) the executables.