- example: string class

	class String {
	public:
		String(const char s[]="");
		String(const String & s1);
		~String();

	private:
		char * info;
	};

	String :: String (const char s[])
	{
		info = new char[strlen(s)+1];
		strcpy(info, s);
	}

	String :: String (const String & s1)
	{
		info = new char[strlen(s1.info)+1];
		strcpy(info, s1.info);
	}

	String :: ~String ()
	{
		delete [] info;
	}


String:: String & operator = (const String & rhs)
{
	if (this != &rhs) {  // cover s=s case 
		delete [] info;
		info = new char[strlen(rhs.info)+1];
		strcpy(info, rhs.info);
	}
	return *this;
}

String:: String & operator += (const String & rhs)
{
	char * temp = new char[strlen(info) + strlen(rhs.info) + 1];
	strcpy(temp, info);
	strcat(temp, rhs.info);
	delete [] info;
	info = temp;
	return *this;
}

String operator + (const String & s, const String & t) // friend
{
	String temp(s);  // use copy constructor
	temp += t;      // use class += operator
	return temp;    // local ok bc return by value only
}
// note this function created a new temporary string object, will be deleted
// when temporary copy isn't needed anymore.
// eg:
//	String s("hello"), t;
//	t = s + " world";     // constructor called for world





String:: char & operator[] (int i)   // can be on left side of assignment
{	return info[i];   }		// String S("hello"); S[1]='a';	

String:: char operator[] (int i) const;  // for constant string objects
{	return info[i];	}  // const String myname("Joanne"); cout << myname[4];

String:: const char* charString() const;  // type converter
{	return info; }

ostream & operator << (ostream & out, const String & s) // friend
{
	out << s.charString();
}

bool operator == (const String & s, const String & t) // friend
{
	return strcmp(s.info, t.info) == 0;
}

bool operator < (const String & s, const String & t) // friend
{
	return strcmp(s.info, t.info) < 0;
}

bool operator >= (const String & s, const String & t)
{
	return strcmp(s.info, t.info) >= 0;
}