setex.cpp

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#include <algorithm>    // for set_intersection, set_union
#include <functional>   // for less
#include <set>          // for set
#include <iostream>     // for cout, endl, ostream_iterator
#include <iterator>     // for ostream_iterator
#include <sstream>      // for ostringstream
 
#include <examples.h>
 
 
typedef std::set<double, std::less<double>, std::allocator<double> > Set;
 
 
std::ostream& operator<< (std::ostream& out, const Set &s)
{
    std::ostringstream strm;
 
    typedef std::ostream_iterator<double, char, std::char_traits<char> > Iter;
 
    std::copy (s.begin (), s.end (), Iter (std::cout, " "));
 
    const std::ostream::sentry guard (out);
 
    if (guard) {
 
        const std::string data = strm.str ();
 
        if (   std::streamsize (data.size ())
            != out.rdbuf ()->sputn (data.data (), data.size ()))
        out.setstate (std::ios::badbit);
    }
 
    return out;
}
 
 
int main ()
{
    // Create a set and insert 10 element into it.
    Set sd;
 
    for (Set::value_type i = 0; i < 10; ++i)
        sd.insert (i);
 
    // Print out the set.
    std::cout << sd << "\n\n";
 
    // Erase half of the elements in the set.
    Set::iterator sdi = sd.begin();
    std::advance (sdi, sd.size () / 2);
    sd.erase (sd.begin(), sdi);
 
    // Print it out again.
    std::cout << sd << "\n\n";
 
    // Make another set and an empty result set.
    Set sd2, sdResult;
 
    for (Set::value_type j = 1; j < 9; ++j)
        sd2.insert (j + 5);
 
    std::cout << sd2 << std::endl;
 
    // Try a couple of set algorithms.
    std::set_union (sd.begin (),sd.end (),sd2.begin (), sd2.end (),
                    std::inserter (sdResult, sdResult.begin ()));
 
    std::cout << "Union:\n" << sdResult << '\n';
 
    sdResult.erase (sdResult.begin (),sdResult.end ());
 
    std::set_intersection (sd.begin (), sd.end (), sd2.begin (), sd2.end (),
                     std::inserter (sdResult, sdResult.begin ()));
 
    std::cout << "Intersection:\n" << sdResult << '\n';
  
    return 0;
}