Operator Problem

Hello :)

Is there a way to perform mathematical operations with the following custom datatype:

Code:

---

#include <iostream>
#include <string>
#include <vector>
#include <boost/variant.hpp>
#include <boost/lexical_cast.hpp>
using namespace std;

typedef boost::variant< int, string > IntStr;

int main()
{
    //Pre-operation is legal
    IntStr a = 1 + 2; //a = 1+2
    cout << a; //outputs 3
    cout << endl;
   
    //Post-operation is illegal
    IntStr b = 1; //b = 1
    cout << b + 2; //outputs error
    cout << endl;
}

---

Error:
no match for 'operator+' in 'b + 2'


Note:
candidates are: std::_Bit_iterator std:: operator+(ptrdiff_t, const std::_Bit_iterator&)
std::_Bit_const_iterator std:: operator+(ptrdiff_t, const std::_Bit_const_iterator&)

Thanks :)

All you have to do is define the operation. If you wanted your operator+ to be integer addition, you could do something like this:

Code:

---

IntStr operator+(const IntStr& i1, const IntStr& i2)
{
        return IntStr(boost::lexical_cast<int, IntStr>(i1) + boost::lexical_cast<int, IntStr>(i2));
}

---

Of course, operator+ isn't exactly obvious in this case. I could also see operator+ being a concatenation of the strings.