C++ tricks

easy_templating.cpp

#define Data_T(type) template <typename  T> type Data<T>

template<typename T>
class Data {

private:
    T _data;

public:
    Data(T data);

    void show();
};

Data_T()::Data(T data) : _data(data) {}

Data_T(void)::show() {
    cout << this->_data << endl;
}

Function pointer:

class Data{
public:
    void show(){
        cout << "Hello world\n";
    }
};
typedef void (Data::*DataMethod)();

int main(){
    Data d;
    Data* d_ptr = &d;
    DataMethod method = &Data::show;
    (d_ptr->*method)();
}