#include <iostream>
#include <string>

template < class T,
           class = typename std::enable_if<std::is_integral<T>::value>::type>
std::string operator +(std::string& rhs, const T& lhs)
{
	return rhs + std::to_string(lhs);
}

int main() {
	std::string s("test");
	std::cout << s+'c';
}