1    The String Class

        The elements of the String class are chacter strings. The following operations can be performed on them:

        1. Assignment from one String instance to another.

        2. Type conversion of a String instance to a char *

        3. Indexing.

        4. etc.

• A string object is NOT a C-string. We often speak of char * variables in C as being "strings". A string object is not a char *, it is an instance of the String class.

The String class offers many advantages over the use of char *

1. Assignment (=) and comparison (==) have the meaning we would like them to have. (QUESTION: What meaning do they have for char *?).

2. Storage allocation and de-allocation are handled automatically.

3. Indexing limitations are handled automatically.

---

class String
{
 private:
  unsigned int Buffer_Len;
  char *Buffer;

  inline void Get_Buffer( const unsigned int Max_Length );

 public:
  // Constructors.
  String ( const char * Value = NULL );
  String ( const String & Value );

  // Destructor.
  ~String ( ) { delete [ ] Buffer; }

  // Assignment operator.
  const String & operator = ( const String & Value );

  // Get a single character.
  char & operator [ ] ( unsigned int Index ) const;

  // Type cast to char *.
  operator const char * const ( ) const { return Buffer; }

  // Get the length.
  unsigned int Length ( ) { return strlen( Buffer ); }

private:
  // Friends
  friend int operator == (const String& lhs, const String& rhs);
  friend int operator != (const String& lhs, const String& rhs);
  friend int operator< (const String& lhs, const String& rhs);
  friend int operator> (const String& lhs, const String& rhs);

};
 

• The underlying representation of a string object is as a char* (called Buffer) - it's private.

• The String class also stores the length of the buffer as a private unsigned int.