c++ - Datatypes and polymorphism -

i have design question. want custom datatypes implementing interface. example, using templates (maybe next design isn't correct -because can generic class instead of next- clarifies goal):

template <typename t> class idatatype { public:     virtual t getdata() const = 0;     virtual void setdata(t pdata) = 0; };  class mychar: public idatatype<char> { public:     void setdata(char pdata){...}     char getdata() const{...}  private:     char _data; };  class myint: public idatatype<int> { public:     void setdata(int pdata){...}     int getdata() const{...}  private:     int _data; };  idatatype<int> *data = new myint(); // parametrized interface, bad idea :( data->getdata(); // works ok 

from previous classes, easy attribute corresponding each _data class member. question:

is there way (change design, etc.) implement generic setter , getter in idatatype , type , manipulate _data attribute of each class without using templates in interface?

for example:

class idatatype { public:     // pure virtual getters , setters specialized _data fields. here design question. };  class mychar: public idatatype { public:     void setdata(char pdata){...};     char getdata(){...};  private:     char _data; };  class myint: public idatatype { public:     void setdata(int pdata){...};     int getdata(){...};  private:     int _data; };  idatatype *intdata = new myint(); // no parametrized interface! intdata->getdata(); // how can create method idatatype?  idatatype *chardata = new mychar(); chardata->getdata(); // same here 

note: have no english, apologize errors :)

you achieve in 3 ways, none elegant , error free using template

1. define data union of int/float/char in base class , act on union set/get methods of base class. entire vb (old vb 6) class system works on such data type called variant.
2. return void * base class , cast , use appropriate - yuck & luck!!.
3. return base interface reference getdata though appearing meaningful, has no meaning @ all. 4.