C / C++ / MFC

// test.h

#ifndef _TEST_H_
#define _TEST_H_

template <class type> class Test
{
public:
	
	void SetMember(type Val);
	type GetMember();
	
	Test<type>& Copy();
	
private:
	
	type m_Member;
	
};

#endif // _TEST_H_

// test.cpp

#include "test.h"

template <class type>
void Test<type>::SetMember(type Val)
{
	this->m_Member = Val;
}

template <class type>
type Test<type>::GetMember()
{
	return this->m_Member;
}

template <class type>
Test<type>& Test<type>::Copy()
{
	return *this;
}

// main.cpp

#include <iostream>
#include "test.h"

using namespace std;

int main()
{
	Test<int> tst;
	
	cout << "TEMPLATE TEST PROGRAM..." << endl << endl;
	
	tst.SetMember(68);
	
	cout << "TEST CLASS RETURNS\t" << tst.GetMember() << endl;
	
	Test<int> tst2 = tst.Copy();
	
	cout << "TEST CLASS 2 RETURNS\t" << tst2.GetMember() << endl;
	
	cout << "Press any key to end..." << endl;
	
	cin.get();
}

------ Build started: Project: template_test, Configuration: Debug Win32 ------

Compiling...
test.cpp
Linking...

main.obj : error LNK2019: unresolved external symbol "public: class Test<int> & __thiscall Test<int>::Copy(void)" (?Copy@?$Test@H@@QAEAAV1@XZ) referenced in function _main

main.obj : error LNK2019: unresolved external symbol "public: int __thiscall Test<int>::GetMember(void)" (?GetMember@?$Test@H@@QAEHXZ) referenced in function _main

main.obj : error LNK2019: unresolved external symbol "public: void __thiscall Test<int>::SetMember(int)" (?SetMember@?$Test@H@@QAEXH@Z) referenced in function _main

Debug/template_test.exe : fatal error LNK1120: 3 unresolved externals

template_test - 4 error(s), 0 warning(s)


---------------------- Done ----------------------

    Build: 0 succeeded, 1 failed, 0 skipped

<br />
<br />
int function();     //Prototype<br />
<br />
void TestDlg::OnGo()<br />
{<br />
     SetDlgItemText(IDC_Output, "From OnGo!!!");     //Works fine<br />
     function();  // Call my function<br />
}<br />
<br />
int function()<br />
{<br />
     SetDlgItemText(IDC_Output, "From funtion()!!");    // ERROR<br />
}<br />
<br />