#include <iostream>

using namespace std;

class C_string
{
private:
	char * pstr;
public:
	C_string(char * ps = "none");
	~C_string() { delete [] pstr; }
	char * str() { return pstr; }
};

C_string::C_string(char * ps)
{
	pstr = new char[strlen(ps) +  1 ];
	strcpy(pstr,ps);
}

void f(C_string c_str)
{
	cout << c_str.str();
}

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

	{
		C_string c("abc");
		f(c);
	}

	return  0 ;
}

public:
  C_string& operator=(const C_string& str){cout << "operator =\n"; return *this;} ;

...
class C_string
{
private:
	C_string(const C_string&);
	C_string& operator=(const C_string&);

...

#include <iostream>
using namespace std;

class C_string
{
private:
	char * pstr;

public:
	C_string(char * ps = "none");
	~C_string() { delete [] pstr; }

	C_string(const C_string&);
	C_string& operator=(const C_string&);

	char * str() const { return pstr; };
};

C_string::C_string(char * ps)
{
	pstr = new char[strlen(ps) +  1 ];
	strcpy(pstr,ps);
}

C_string::C_string(const C_string& c)
{
	pstr = new char[strlen(c.str()) +  1 ];
	strcpy(pstr, c.str());
}
C_string& C_string::operator=(const C_string& c)
{
	if(this != &c)
	{
		delete[] pstr;
		pstr = new char[strlen(c.str()) +  1 ];
		strcpy(pstr, c.str());
	}
	return *this;
}

void f(C_string c_str)
{
	cout << c_str.str() << endl;;
}

int main()
{
	C_string c1, c2, c3("abc");
	c1 = c3;
	f(c1);
	f(c2);
	f(c3);

	return  0 ;
}