What am I doing wrong? (Operator overloading)

[UserName112]

#ifndef TEST
#define TEST
using namespace std;

template <typename T>
class Test
{
private:
    T number;
public:
Test();
Test(T);
template <typename T> friend Test<T> operator+(Test<T> &a, Test<T> &b);
template <typename T> friend ostream& operator<<(ostream& out, Test<T> &obj);
};

template <typename T>
Test<T>::Test(T num1)
{
    number = num1;
}

template <typename T>
Test<T> operator+(Test<T> &a, Test<T> &b)
{
    return Test<T>(a.number + b.number);
}

template <typename T>
ostream& operator<<(ostream& out, Test<T> &obj1)
{
    out<< obj1.number;
    return out;
}

#endif

#include <iostream>
#include "Test.h"
using namespace std;
int main()
{
    Test <int> obj1(5);
    Test <int> obj2(2);
    Test <int> obj3;

    obj3 = obj1 + obj2;
    cout << obj3;
    return 0;
}

I keep getting an error that says: "LNK2019: unresolved external symbol "public: __thiscall Test<int>::Test<int>(void)" (??0?$Test@H@@QAE@XZ) referenced in function _main"

[gardhr]

#ifndef TEST
#define TEST
using namespace std;

template <typename T>
class Test
{
private:
    T number;
public:
Test();
Test(T);
template <typename T> friend Test<T> operator+(Test<T> &a, Test<T> &b);
template <typename T> friend ostream& operator<<(ostream& out, Test<T> &obj);
};

template <typename T>
Test<T>::Test(T num1)
{
    number = num1;
}

template <typename T>
Test<T> operator+(Test<T> &a, Test<T> &b)
{
    return Test<T>(a.number + b.number);
}

template <typename T>
ostream& operator<<(ostream& out, Test<T> &obj1)
{
    out<< obj1.number;
    return out;
}

#endif

#include <iostream>
#include "Test.h"
using namespace std;
int main()
{
    Test <int> obj1(5);
    Test <int> obj2(2);
    Test <int> obj3;

    obj3 = obj1 + obj2;
    cout << obj3;
    return 0;
}

I keep getting an error that says: "LNK2019: unresolved external symbol "public: __thiscall Test<int>::Test<int>(void)" (??0?$Test@H@@QAE@XZ) referenced in function _main"

1) You've declared an empty constructor, so define it.
2) The friend functions can't reuse the template parameter 'T' - name theirs somethings else.
3) The copy constructor should take a constant reference to 'T'.

[UserName112]

Got it. Thanks!