Constructor with variable number of arguments

I want to add a constructor that could allow a variable number of arguments. caller is a function that could call other functions with their arguments(something simliar to thread but for calling functions only). I already made it with a function template

template <class C,class ... _Args >
void caller(C(*f) ( _Args ... __args ), _Args ... __args ){(*f ) ( __args ...) ;}

But I need to have a class because it also should make an object of this class. something like this.

caller()

I made a class for caller with a constractor that could call other functions with a known number of arguments.

#include <iostream>
class caller  {
public:
caller(){std::cout<<"Constructor default";  }
caller(void (*Optype)(int),int a){Optype(a);std::cout<<"Constructor 1";  }
//*** Constructor for variable number of arguments**
};

and it works correctly with following code

#include <iostream>
#include "caller"
using namespace std;
void foo(int a){
  cout<<a<<endl;
}
int main()
{
  caller c;
  caller(); 
  caller(foo,2);  
  return 1;
}

I want to know how can I add a constructor which works with different numbers of variables and is it possible it allows different types of variables too? I ask for something like the function template that I already made but in the class.