RPN calculator c++

/* Antonio Villanueva RPN calculator
*/

#include <iostream>
#include <vector>
#include <cmath> // std::nan
using namespace std;

class CalculadoraRPN{

    public :
    CalculadoraRPN (double n1 , double n2, double op) : n1(n1) , n2(n2) ,op(op){};

    double calculaOperacion(){
        switch (op){
            case '*':
            case 'x':return n1*n2;
            case '+':return n1+n2;
            case '-':return n1-n2;
            case '/':return n2!=0 ? n1/n2 :std::nan("");

        }
        return std::nan("");
    };

    private:
    double n1,n2;
    char op;

};

int main(void)
{
    CalculadoraRPN calculo(5.0,0.0,'/');
    cout <<calculo.calculaOperacion()<<endl;

    return 0;
}