Library: Iterators
ostreambuf_iterator output_iterator
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