Undefined reference error when trying to overload the >> operator in a template class

Question

I am trying to overload the >> operator in my template class as a friend function.The problem occurs when I want to read an object of that class;I get the following error: undefined reference to `std::istream& operator>>(std::istream&, ContBancar&)'. I have checked this post (overloading friend operator<< for template class) and I have tried the second approach which is found in the code below.

//ContBancar.h
//included all the necessary libraries

template<class T> class ContBancar;
template<class T> istream& operator>>(istream&, ContBancar<T>&);

template<class T>
class ContBancar {
    string detinator;
    string dataDeschidere;
    T sold;
public:
    ContBancar(string det="DefaultDestinatar", string data="NoData", T sol=T(0)):detinator(det),dataDeschidere(data),sold(sol){}
    friend istream& operator >> <T>(istream &, ContBancar<T> &);

};

//ContBancar.cpp
#include "ContBancar.h"

template <class T>
istream & operator>>(istream &in, ContBancar<T> &ob)
{
    in>>ob.detinator;
    in>>ob.sold;
    in>>ob.dataDeschidere;
    return in;
}