Unordered lists

The example:

// list.cc
// Example of use of list

#include <hush/list.h>
#include <iostream.h>


// ALWAYS pass complex value parameters with const& !
void printlist(const list<int>& l)
{
    iter<int> listiter = l;             // see explanation in main
    int* intptr = 0;

    while (intptr = listiter())
    {
        cout << *intptr << " ";
    }
    cout << endl;
}


int main()
{
    list<int> l1;                       // create an empty list of ints
    int i1 = 27, i2 = 3, i3 = 81;       // some integers

    cout << "length of l1 is " << l1.length() << endl;
                                        // retrieving the length of a list

// insert some elements
    l1.insert(&i1);                     // IMPORTANT: list stores only
                                        // POINTERS to elements, so something
                                        // like l1.insert(3) won't work!
                                        // see the effect of this later on
    l1.insert(&i2);
    l1.insert(&i3);

    cout << "length of l1 is " << l1.length() << endl;

// now we will iterate over the whole list:
    iter<int> listiter = l1;            // create an iterator for a list, more
                                        // specifically, an iterator for our
                                        // created list
    int* intptr = 0;                    // this POINTER to an integer will
                                        // be used for the iteration
    while (intptr = listiter())
    {
        cout << "item = " << *intptr << endl;
    }

    cout << "2nd element of l1 = " << *(l1[1]) << endl;
                                        // retrieving an element by index

// an example of datastructure sharing between lists:
    list<int> l2 = l1;                  // creates an alias of l1

    printlist(l2);

    int* eltptr = l2.head();            // retrieve the first element
    *eltptr = 7;                        // change it
    printlist(l2);                      // of course, l2 has changed, but
    printlist(l1);                      // the elements in l1 have changed too!

// since lists only store POINTERS to elements, the elements that were added
// will be changed:
    cout << "i1 is now " << i1 << endl;

// and vice versa:
    i2 = 128;
    printlist(l1);

// show effect of aliasing:
    l1.remove(l1.head());               // remove some elements
    l1.remove(l1.head());
    printlist(l1);                      // l1 is a lot shorter
    printlist(l2);                      // l2 changes too

    return 0;
}