Thread: Help with CString class and operator+ overloading

Could someone help me with operator overloading and my String class. I'm stuck with the '+' operator, which should "return a new object of type CString that contains the contents of 'this' Cstring with the contents of the parameter Cstring concatinated." It supposed to work in 3 different ways: 'CString + Cstring', 'Cstring + char *', and 'char * + Cstring'. I've got no problems with the first two, just the third one that's giving me problems. I think I need a friend function that receives a char * and a CString, then returns a CString, but I'm not sure how to implement that.

Here's some code:

Code:

class CString
{
	
	friend class CStringIterator;
	friend CString &operator+ (const char * lvalue, const CString & rvalue);
	friend ostream &operator<<(ostream &stream, const CString &rvalue); //works
	friend istream &operator>>(istream &stream, CString &rvalue); //works
	friend bool operator== (const CString & lvalue, const CString & rvalue);


   public:
	   CString(); //works
	   CString(CString &string); //works
	   CString(char*); //works
	   ~CString(); //works
	   //void Set(char* NewString);
	   void Set(CString NewString);
	   bool IsEmpty() const; //works
	   int Length() const;//works
	   //void Append(char* NewString); //works but don't need
	   void Append(CString &NewString); //works
	   //bool Compare(char* NewString); 
	   bool Compare(CString NewString) const;//works
	   void Empty(); //works   
	   void Display() const; //works
	   void Contain_My_Name() const; //works


	   /*////////  Begin Overloaded Operators ////////////////*/

	   const CString &CString::operator=(const CString & rValue);
	   CString &operator+ (const CString & rvalue);
	   void CString::operator+=(const CString &rvalue);
	   bool CString::operator== (const CString & rvalue) const;
	   bool CString::operator< (const CString & rvalue) const;
	   bool CString::operator> (const CString & rvalue) const;
	   bool CString::operator<= (const CString & rvalue) const;
	   bool CString::operator>= (const CString & rvalue) const;
	   bool CString::operator!= (const CString & rvalue) const;


   private:
	   char* pString;
	   void SetString(const char * string, int length);

};

Member function for overload operator+ that works great:

Code:

CString &CString::operator+ (const CString & rvalue)
{
	int l1 = Length();
	int l2 = rvalue.Length();
	int length = l1 + l2;
	
	char *tempPtr = new char[length + 1];

	strcpy(tempPtr, pString);
	strcpy(tempPtr + l1, rvalue.pString);

	delete [] pString;
	
	pString = tempPtr;

	return * this;
}

Friend function for operator+ that doesn't work:

Code:

CString &operator+ (const char * lvalue, const CString & rvalue)
{
	int l1, l2;
	l1 = strlen(rvalue.pString);
	l2 = rvalue.Length();

	char *tempPtr = new char[l1 + l2 + 1];

	strcpy(tempPtr, lvalue);
	strcpy(tempPtr + l1, rvalue.pString);

	CString new_string;

	new_string = tempPtr;

	delete [] tempPtr;
    
	return * new_string;
}

Thanks for any help in advance!