illegal member initialization: 'counter' is not a base or member

i have a small templatized class which just checks for object sizes of different object types: (note: i am compiling with visual studio 2017 cl compiler). All i wanted was to instantiate the template partially and fully. But i am getting compiler error.

template <class T1, class T2>
class Templatized {
private:
    int m_counter;
    string m_classname;
public:
    //c-tor
    Templatized() :counter(0), classname(static_cast <string> ("Templatized")) {}

    int get_counter() {
        return m_counter;
    }

    string know_class_name() {
        return m_classname;
    }

    bool is_bigger_name(T1 one, T2 two) {
        return ((one.know_class_name()).length() > (two.know_class_name()).length());
    }

    bool is_bigger_object_size(T1 one, T2 two) {
        return (sizeof(one) > sizeof(two));
    }

    //variadic template

    ~Templatized (){
    }
};

class Int_class {
private:
    int var1; 
public:
    int square_int() {
        return var1 * var1; 
    }

    string know_class_name() {
        return static_cast <string> ("Int_class");
    }
};

class Float_class {
private:
    float m_var_f; 
public:
    float double_float () {
        return 2.0f * m_var_f;
    }

    string know_class_name() {
        return static_cast <string> ("Float_class");
    }
};

and here are the client code, but i am not able to compile them:

Templatized <Int_class, Float_class> templatized;
    Int_class intclass; 
    Float_class floatclass; 

    cout << "is int class object size is smaller: " 
        << templatized.is_bigger_object_size(intclass, floatclass) << endl;
    cout << "Has IntClass bigger name: "
        << templatized.is_bigger_name(intclass, floatclass) << endl;

The compiler cries with following error:

1>d:\code\integration\inc\Templates.hpp(14): error C2614: 'Templatized<Int_class,Float_class>': illegal member initialization: 'counter' is not a base or member
1>d:\code\integration\inc\Templates.hpp(14): note: while compiling class template member function 'Templatized<Int_class,Float_class>::Templatized(void)'
1>D:\code\integration\client\integrationClient.cpp(63): note: see reference to function template instantiation 'Templatized<Int_class,Float_class>::Templatized(void)' being compiled
1>D:\code\integration\client\integrationClient.cpp(63): note: see reference to class template instantiation 'Templatized<Int_class,Float_class>' being compiled