Re: How to use the istream and ostream?

From:

"Tom Widmer [VC++ MVP]" <tom_usenet@hotmail.com>

Newsgroups:

microsoft.public.vc.language

Date:

Thu, 03 Aug 2006 12:27:43 +0100

Message-ID:

<emaOX$utGHA.4460@TK2MSFTNGP04.phx.gbl>

Ma Xiaoming wrote:

Dear ladies and gentlemen,

I created a header file followed by a book -- C++ Primer 3rd Edition.
The header file is as the following:

//////////////////////////////////////////////////////////////////

#ifndef STRING_CLASS_H
#define STRING_CLASS_H

#include <iostream>

Instead
#include <iosfwd>

istream& operator>>( istream&, String& );
ostream& operator<<( ostream&, const String& );

Instead
Class String;
std::istream& operator>>( std::istream&, String& );
std::ostream& operator<<( std::ostream&, const String& );

class String;

class String {
public:
  String();
  String( const char* );
  String( const String& );

  ~String();

  String& operator=( const String& );
  String& operator=( const char* );

  bool operator==( const String& );
  bool operator==( const char* );

Instead:
bool operator==( const String& ) const;
bool operator==( const char* ) const;
//also:
friend bool operator==(const char* s1, const String& s2)
{
return s2 == s1;
}
//operator!=?

char& operator[]( int );

int size() { return _size; }

Instead
int size() const { return _size; }

  char* c_str() { return _string; }

private:
  int _size;
  char *_string;
};

#endif /* STRING_CLASS_H */

You also need const overloads of the accessors. But what's wrong with
std::string?

Tom