## CGAL::Istream_iterator<T,Stream>

### Definition

The class Istream_iterator<T,Stream> is an input iterator adaptor for the input stream class Stream and value type T. It is particularly useful for classes that are similar but not compatible to std::istream.

#include <CGAL/IO/Istream_iterator.h>

### Creation

Istream_iterator<T,Stream> i;
| creates an end-of-stream iterator i. This is a past-the-end iterator, and it is useful when constructing a range.
Istream_iterator<T,Stream> i ( Stream& s);
| creates an input iterator i reading from s. When s reaches end of stream, this iterator will compare equal to an end-of-stream iterator created using the default constructor.

### Operations

i fulfills the requirements for an input iterator.

### Example

The following program reads points from a Window_stream until the right mouse button gets clicked.

    #ifndef CGAL_USE_LEDA
    #include <iostream>
    int main(){ std::cout << "This demo needs LEDA" << std::endl; return 0;}
    #else

    #include <CGAL/Cartesian.h>
    #include <CGAL/IO/Istream_iterator.h>
    #include <CGAL/IO/Window_stream.h>
    #include <iostream>
    #include <algorithm>

    typedef CGAL::Cartesian<double>::Point_2                   Point;
    typedef CGAL::Istream_iterator<Point, CGAL::Window_stream> Iterator;

    #ifdef CGAL_USE_CGAL_WINDOW
    #define leda_window CGAL::window
    #define leda_green  CGAL::green
    #endif

    void init_window( leda_window& W) {
        CGAL::cgalize( W);
        W.set_fg_color( leda_green);
        W.display();
        W.init(-1.0, 1.0, -1.0);
    }

    int main () {
        CGAL::Window_stream window( 512, 512);
        init_window(window);
        std::copy( Iterator(window), Iterator(),
                   std::ostream_iterator<Point>(std::cout,"\n"));
        return 0;
    }

    #endif