In class sample program demonstrating header files won't compile?

[Tieria]

Hey guys,

In my C++ course we have just started dealing with programs that are comprised of a header, implementation and a main file. I am trying to get a sample program I was given in class to compile so I can use it as a template for the actual assignment on this topic I have to complete. Something isn't working quite right and while I imagine the mistake I have made is very simple I am unable to find a typo. I also cannot seem figure out what the error printout is telling me.

 // START OF HEADER FILE CALLED "c1.h"
class counter
{
public:
		int currentcount();
		void addone();
		void subone();
		counter();
		counter(int);
private:
		int cur_count;	
};
// END OF HEADER FILE

// START OF IMPLEMENTATION FILE CALLED "c1.cpp" 
#include <iostream>
#include "c1.h"

using namespace std;

int counter::currentcount()
{
	return cur_count;
}
void counter::addone()
{
	cur_count++;
}
void counter::subone()
{
	cur_count--;
}
counter::counter()
{
	cur_count = 0;
}
counter::counter(int i)
{
	cur_count = i;
}	
// END OF IMPLEMENTATION FILE

// START OF MAIN PROGRAM FILE CALLED "c2.cpp"
#include "c1.cpp"

using namespace std;

int main()
{
	counter c1;
	cout << c1.currentcount() << endl;
	c1.addone();
	c1.addone();
	cout << c1.currentcount() << endl;

	return 0;
}
// END OF MAIN PROGRAM FILE 

I am attempting to run this program in Visual Studio 2013 on a Windows 7 machine. I'm not sure if I am doing this correctly or not but in Visual Studio I have created a project and created c1.h in the project subfolder "Header Files", c1.cpp in "Resource Files" and c2.cpp in "Source Files". These are all listed on the left of my interface in a box titled "Solution Explorer". Hopefully that's how it's supposed to be done, anyway the error readout I am currently getting is...

Error 1 error LNK2005: "public: __thiscall counter::counter(int)" (??0counter@@QAE@H@Z) already defined in c1.obj c:\Users\Steve\documents\visual studio 2013\Projects\Project7\Project7\c2.obj Project7
Error 2 error LNK2005: "public: __thiscall counter::counter(void)" (??0counter@@QAE@XZ) already defined in c1.obj c:\Users\Steve\documents\visual studio 2013\Projects\Project7\Project7\c2.obj Project7
Error 3 error LNK2005: "public: void __thiscall counter::addone(void)" (?addone@counter@@QAEXXZ) already defined in c1.obj c:\Users\Steve\documents\visual studio 2013\Projects\Project7\Project7\c2.obj Project7
Error 4 error LNK2005: "public: int __thiscall counter::currentcount(void)" (?currentcount@counter@@QAEHXZ) already defined in c1.obj c:\Users\Steve\documents\visual studio 2013\Projects\Project7\Project7\c2.obj Project7
Error 5 error LNK2005: "public: void __thiscall counter::subone(void)" (?subone@counter@@QAEXXZ) already defined in c1.obj c:\Users\Steve\documents\visual studio 2013\Projects\Project7\Project7\c2.obj Project7
Error 6 error LNK1169: one or more multiply defined symbols found c:\users\steve\documents\visual studio 2013\Projects\Project7\Debug\Project7.exe 1 1 Project7


Any help on what I am missing here would be greatly appreciated. I just need to be able to run a program that is split up into multiple files so I can get the code for my actual assignment to work.

Thanks.

[nvrmnd]

you should include the header file c1.h in c2.cpp instead of the implementation file

[Tieria]

I tried doing what you suggested but I must not be understanding you correctly. Would you mind listing off what you think the #include statements should be for each of my files (c1.h : c1.cpp : c2.cpp)?

[nvrmnd]

You only need to change this :

// START OF MAIN PROGRAM FILE CALLED "c2.cpp"
#include "c1.h" // <<<==

using namespace std;

int main()
{
	counter c1;
	cout << c1.currentcount() << endl;
	c1.addone();
	c1.addone();
	cout << c1.currentcount() << endl;

	return 0;
}
// END OF MAIN PROGRAM FILE  

[Tieria]

Thanks that worked! I am still a bit confused as to how the compiler knows to go and get c1.cpp though? There is no longer a #include "c1.cpp" statement in any of the files.

[Tieria]

Ohhhh! Is it because both the header file and the implementation files have the same name "c1" just different extensions?

[Zhuge]

You have the source (cpp) files together in the project, so they will be linked together. It has nothing to do with their names.

[Tieria]

Oh ok, thanks!