operator overloading

[dakotabk]

hello everyone!
I met some problems with pointer here:

////////////////////////code//////////////////////////////////
//class's declaration 
//file FunnyString.h
#ifndef FUNNYSTRING_H
#define FUNNYSTRING_H
#include <cassert>
#include <iostream>

using namespace std;
class FunnyString
{
	friend istream &operator>>( istream&, FunnyString& );
	friend ostream &operator<<( ostream&, FunnyString&) ;
public:
	FunnyString(char* = 0);
	~FunnyString()
	{
		delete [] data;
	}
	FunnyString( FunnyString& ); //copy constructor.
	FunnyString  operator+( FunnyString& );
	FunnyString & operator=(  FunnyString& ); //assigment operator.
private:
	void SetString( char*);
	char GetOneCharacter( const int & index )
	{
		assert( ( index < len ) && index>= 0 );
		return data[index];
	}
	void CutBeginCharacter();
	void SelfCutEndCharacter();
	char* data;
	int len;
};
#endif
///////////////////////////code///////////////////////////////////////////////
-----------------------------code--------------------------------------------
//FunnyString class's definition.
//FunnyString.cpp file.
#include "FunnyString.h"
#include <iostream>
#include <cassert>
using namespace std;

FunnyString::FunnyString(char *s )
:len(strlen(s)+1)
{
	SetString(s);
}
FunnyString::FunnyString( FunnyString & s)
{
	SetString(s.data);
}
FunnyString& FunnyString::operator= (  FunnyString& s)
{
	if ( &s != this ) //prevent self assigment.
	{
		if ( s.len != len )
		{
			delete [] data;
			SetString(s.data);
		}
	}
	else cout << "Self assigment\n";
	return *this;
}
FunnyString  FunnyString::operator+( FunnyString & s)
{
	FunnyString fString1(data);
	FunnyString fString2(s.data);
        FunnyString &tmp = fString1;
	while ( fString1.data[len-2] == fString2.data[0] )
	{
		fString1.SelfCutEndCharacter();
		fString2.CutBeginCharacter();
	}
	strcat(fString1.data,fString2.data);
	return tmp;
}
ostream& operator<< (ostream& output,FunnyString& s )
{
	output << s.data;
	return output;
}
istream& operator>> (istream& input, FunnyString& s)
{
	char tmp[100];
	input >> tmp;
	s.data = tmp;
	return input;
}
void FunnyString::SetString( char* s )
{
	if ( 0 != s )
	{
		len = strlen(s)+1;
		data = new char[len];
		strcpy(data,s);
	}
	else 
	{
		len = 1;
		data = 0;
	}
}
void FunnyString::CutBeginCharacter()
{
	char* tmp = new char[len-1];
	for ( int i = 0; i < len - 2; i++)
	{
		tmp[i]=data[i+1];
	}
	tmp[len-2] = 0;
	delete [] data;
	SetString(tmp);
	delete [] tmp;
}
void FunnyString::SelfCutEndCharacter()
{
	char* tmp = new char[len-1];
	strncpy(tmp,data,len-2);
	tmp[len-2] = 0;
	delete [] data;
	SetString(tmp);
	delete [] tmp;	//release tmp;
}

-----------------------------code-------------------------------------

The operator+ function met a pointer problem(I don't know why, I just want this function does not change the data, so I created 2 new FunnyString objects and handle them. This function return a reference of FunnyString!!!- maybe when the function end, all the data will be destruct by destructor which released the char* data, so function can not return it).But I can't prevent it. this is a operator overloading, it can not contain more parameter,so how can I return in this function?