#include <iostream>
#include <string>

int main()
{
    {
        std::string (&plus)(std::string const&, std::string const&) = &std::operator+;
        std::string a ("Hello, "), b("World!");
        std::cout << plus(a, b) << std::endl;
    }
    
    {
        int (&plus)(int const&, int const&) = &operator+;
        int a (3), b(4);
        std::cout << plus(a, b) << std::endl;
    } 
}