ostreambuf_iterator

Module:  Standard C++ Library   Library:  Iterators

ostreambuf_iterator  output_iterator

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Members

char_type failed() operator*()

operator++() operator=() ostreambuf_iterator()

ostream_type streambuf_type traits_type

Writes successive characters onto the stream buffer object from which it was constructed

#include <iterator> 

namespace std {
  template<class charT, class traits = char_traits<charT> >
  class ostreambuf_iterator;
}

The class template ostreambuf_iterator writes successive characters onto the stream buffer object from which it was constructed. operator=() is used to write the characters. In case of failure, the member function failed() returns true.

namespace std {

  template<class charT, class traits = char_traits<charT> >
  class ostreambuf_iterator 
    : public iterator <output_iterator_tag, void, 
                       void, void, void>
  {
  public: 

    typedef charT char_type;
    typedef traits traits_type;
    typedef basic_streambuf<charT, traits> streambuf_type;
    typedef basic_ostream<charT, traits> ostream_type;

    ostreambuf_iterator(ostream_type& s) throw();
    ostreambuf_iterator(streambuf_type *s) throw();
    ostreambuf_iterator& operator=(char_type c);

    ostreambuf_iterator& operator*();
    ostreambuf_iterator& operator++();
    ostreambuf_iterator operator++(int);
       
    bool failed( ) const throw();
    
  };
}

char_type

The type char_type is a synonym for the template parameter charT.

ostream_type

The type ostream_type is a synonym for the type basic_ostream<char_type, traits_type>.

streambuf_type

The type streambuf_type is a synonym for the type basic_streambuf<char_type, traits_type>.

traits_type

The type traits_type is a synonym for the template parameter traits.

ostreambuf_iterator(ostream_type& s) throw();

Constructs an ostreambuf_iterator that uses the basic_streambuf object pointed to by s.rdbuf()to output characters. If s.rdbuf() is a null pointer, calls to the member function failed() return true.

ostreambuf_iterator(streambuf_type *s) throw();

Constructs an ostreambuf_iterator that uses the basic_streambuf object pointed to by s to output characters. If s is a null pointer, calls to the member function failed() return true.

ostreambuf_iterator& 
operator=(char_type c); 

Inserts the character c into the output sequence of the attached stream buffer. If the operation fails, calls to the member function failed() return true.

ostreambuf_iterator& 
operator++();

Returns *this.

ostreambuf_iterator 
operator++(int); 

Returns *this.

ostreambuf_iterator 
operator*();

Returns *this.

bool 
failed() const 
  throw();

Returns true if the iterator failed while inserting a character. Otherwise returns false.

//
//  ostreambuf_iterator.cpp
//
 
#include <iostream>   // for cout, endl
#include <iterator>   // for istreambuf_iterator,
                      //     ostreambuf_iterator
#include <fstream>    // for filebuf

#include <stdio.h>    // for tmpnam and remove


int main ( )
{
    char namebuf [L_tmpnam];

    // create a temporary filename
    const char *fname = tmpnam (namebuf);

    if (!fname)
        return 1;

    // create a filebuf object
    std::filebuf buf;

    // open the file and link it to the filebuf object
    buf.open (fname, std::ios::in | std::ios::out |
                     std::ios::trunc);

    // create an ostreambuf_iterator and link it to 
    // the filebuf object
    std::ostreambuf_iterator<char, std::char_traits<char> >
                            out_iter (&buf);

    // output into the file using the ostreambuf_iterator
    for (char i = 64; i < 127; i++)
        out_iter = i;

    // seek to the beginning of the file
    buf.pubseekpos(0);
  
    // create an istreambuf_iterator and link it to 
    // the filebuf object
    std::istreambuf_iterator<char, std::char_traits<char> >
                            in_iter (&buf);

    // construct an end of stream iterator
    std::istreambuf_iterator<char, std::char_traits<char> >
                            end;

    std::cout << std::endl;

    // output the contents of the file
    while (!in_iter.equal (end))
        std::cout << *in_iter++;

    std::cout << std::endl;

    // remove temporary file
    remove (fname);

    return 0;
}


Program Output:

@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~

basic_streambuf, basic_ostream, istreambuf_iterator

ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 24.5.4

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