#include <iostream>
#include <string>
void foo(std::string& s) { std::cout << "l-value reference" << std::endl; }
void foo(std::string&& s) { std::cout << "r-value reference" << std::endl; }
int main(int argc, char* argv[])
{
std::string s;
foo(s);
foo(std::string());
return 0;
}
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