C++ ADL example

adl.cpp

#include <iostream>

namespace other 
{

struct Foo {};

void func(const Foo& foo) { std::cout << "yes!\n"; }

}  // namespace other

struct Bar {};

void func(const Bar& bar) { std::cout << "no!\n"; }

int main(int, char**) {
    // thanks to ADL it works
    // func is used by unqualified name so ADL looks for a suitable element
    func(other::Foo());
    func(Bar());
    return 0;
}