g++에서 연산자 overriding과 복사생성자가 함께 쓰여진 경우

#include <iostream>
#include <string.h>
 
using namespace std;
 
class CopyCons
{
	char * st;
public:
	CopyCons()
	{
		st = NULL;
	}
 
	CopyCons(char * st);
	CopyCons(CopyCons &s);
 
	CopyCons operator + (char * st);
 
	virtual ~CopyCons();
	char * get_st()
	{
		return st;
	}
};
 
CopyCons::CopyCons(char * st)
{
	this->st = new char[strlen(st) + 1];
	strcpy(this->st, st);
}
 
CopyCons::CopyCons(CopyCons &s)
{
	this->st = new char[strlen(s.st) + 1];
	strcpy(this->st, s.st);
}
 
CopyCons::~CopyCons()
{
	if(st != NULL)
		delete [] st;
}
 
CopyCons CopyCons::operator + (char * s)
{
	char * buffer = new char[strlen(st) + strlen(s) + 1];
	strcpy(buffer, st);
	strcat(buffer, s);
	CopyCons t(buffer);
	delete [] buffer;
 
	return t;	
}
 
int main()
{
	CopyCons c1("hello"), c2;
	c2 = c1 + " world~!";
	cout << "um? " << c2.get_st() << endl;
}