Software Design Patterns: Iterator pattern using C++

Why?
Provide a way to access the elements of a container (or aggregate or collection) object sequentially without exposing its underlying representation

Code:

#include <iostream>

using namespace std;

class ListSequence

{

private:

    int items[10];

    int index;

    int sz;

public:

    friend class ListSequenceIterator;

    ListSequence()

    {

        index = -1;

        sz = 0;

    }

    void push_back(int in)

    {

        items[++index] = in;

        sz++;

    }

    int pop_back()

    {

        sz--;

        return items[index--];

    }

    bool isEmpty()

    {

        return (sz == 0);

    }

    int size()

    {

        return sz;

    }

};

class ListSequenceIterator

{

private:

    const ListSequence& listSequence;

    int index;

public:

    ListSequenceIterator(const ListSequence& l): listSequence(l)

    {

        index = 0;

    }

    void operator++() // prefix notation

    {

        index++;

    }

    bool is_not_the_end()

    {

        return index != listSequence.sz;

    }

    int operator*()

    {

        return listSequence.items[index];

    }

};

int main()

{

    ListSequence list1;

    for (int i = 1; i < 5; i++) {

        list1.push_back(i);

    }

    cout << "list1.size(): " << list1.size() << endl;

    list1.pop_back();

    list1.push_back(-1);

    list1.push_back(-2);

    cout << "list1.size(): " << list1.size() << endl;

    ListSequenceIterator listSequenceIterator(list1);

    cout << "ListSequence content using ListSequenceIterator: " << endl;

    for ( ; listSequenceIterator.is_not_the_end(); )

    {

        cout << *listSequenceIterator << " ";

        ++listSequenceIterator;

    }

    cout << endl;

    return 0;

}

Sample run:

list1.size(): 4

list1.size(): 5

ListSequence content using ListSequenceIterator: 1 2 3 -1 -2