Question

I tried implicit conversion, but this doesn’t work.

#include <string>
#include <iostream>

struct MyClass
{
    operator std::string() { return "bar"; }
};

int
main( int argc, char* argv[] )
{
    MyClass x;

    std::cout << std::string( "foo" ) + x << std::endl;
    return 0;
}

Answer 1

Implicit conversion won’t work since string’s operator+ is templated and you’re deducing the template parameters. This looks like a better explanation of what’s happening: https://stackoverflow.com/a/8892794/964135

I would just do a cast or write a non-template operator+.

---

A stupid solution is to not deduce the types and then it will do the implicit conversion:

std::cout << std::operator+<char, std::char_traits<char>, std::allocator<char> >(std::string( "foo" ), x) << std::endl;