Here's a simple example of using class templates in C++. This code works.
#include <iostream>
using namespace std;
template <class T>
class Test {
public:
Test();
void print();
private:
int i;
};
template <class T>
Test<T>::Test() {
i=1;
cout<<"New instance"<<endl;
}
template <class T>
void Test<T>::print() {
cout<<"Test"<<endl;
}
int main() {
Test<int> i;
i.print();
return 0;
}
So when I separate this code in 3 files: main.cpp, Test.h, Test.cpp:
//Test.h
#include <iostream>
using namespace std;
template <class T>
class Test {
public:
Test();
void print();
private:
int i;
};
//Test.cpp
#include "Test.h"
template <class T>
Test<T>::Test() {
i=1;
cout<<"New instance"<<endl;
}
template <class T>
void Test<T>::print() {
cout<<"Test"<<endl;
}
//main.cpp
#include "Test.h"
using namespace std;
int main() {
Test<int> i;
i.print();
return 0;
}
I get an errors:
1>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall Test<int>::print(void)" (?print@?$Test@H@@QAEXXZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall Test<int>::Test<int>(void)" (??0?$Test@H@@QAE@XZ) referenced in function _mai
1>C:\Programming\C++\stuff\templass\Debug\templass.exe : fatal error LNK1120: 2 unresolved externals
I use Microsoft Visual C++ 2010 Express. So I searched a lot about unresolved external symbol but didn't find anymore for this case. So what's my mistake?
