list.cpp

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#include <algorithm>   // for find
#include <list>        // for list
#include <string>      // for string
#include <iostream>    // for cout
 
#include <examples.h>
 
 
typedef std::list<std::string, std::allocator<std::string> > StringList;
 
 
// stream out a list of strings
std::ostream& operator<< (std::ostream &out, const StringList &l)
{
    // create a sentry object to guard the stream
    const std::ostream::sentry guard (out);
 
    if (guard) {
 
        // the guard succeeded in preparing the stream for output
 
        for (StringList::const_iterator i = l.begin (); i != l.end (); ++i) {
 
            // insert the string into the stream object's buffer
            const std::streamsize n =
                out.rdbuf ()->sputn ((*i).data (), (*i).size ());
 
            // insert the space character into the buffer
            if (   std::streamsize ((*i).size ()) != n
                ||    std::ostream::traits_type::to_int_type (' ')
                   != out.rdbuf ()->sputc (' ')) {
 
                // set badbit if either operation failed
                out.setstate (std::ios::badbit);
                break;
            }
        }
    }
 
    return out;
}
 
 
int main ()
{
    // Create a list of critters.
    StringList critters;
 
    // Insert a few critters.
    critters.insert (critters.begin (), "antelope");
    critters.insert (critters.begin (), "bear");
    critters.insert (critters.begin (), "cat");
 
    // Print out the list.
    std::cout << critters << '\n';
 
    // Change cat to cougar.
    *std::find (critters.begin (),critters.end (), "cat") = "cougar";
    std::cout << critters << '\n';
 
    // Put a zebra at the beginning, an ocelot ahead of antelope,
    // and a rat at the end.
    critters.push_front ("zebra");
    critters.insert (std::find (critters.begin (), critters.end (),
                                "antelope"), "ocelot");
    critters.push_back ("rat");
    std::cout << critters << '\n';
 
    // Sort the list (Use list's sort function since the 
    // generic algorithm requires a random access iterator 
    // and list only provides bidirectional)
    critters.sort ();
    std::cout << critters << '\n';
 
    // Now let's erase half of the critters.
    StringList::size_type half = critters.size () / 2;
    for (StringList::size_type i = 0; i != half; ++i)
        critters.erase (critters.begin ());
 
    std::cout << critters << '\n';
  
    return 0;
}