Re: How to print container elements which are pointers

Zhihao Yuan <>
Mon, 26 Nov 2012 16:41:58 -0800 (PST)
On Thursday, November 8, 2012 8:36:30 PM UTC-6, V.Subramanian, India wrote:

c.officers.push_back(new Person(string("one")));

To expose a pointer-based interface is very dangerous, since it's too
easy to leak a new-ed memory (your sample program already leaked) or
encounter a data corruption if you insist to delete the pointers

Anyway, here is my suggestion: to define a custom iterator.

First, as usual, you need an output operator for Person:

friend ostream& operator<<(ostream& out, Person const& p) {
    out <<;
    return out;

And then, a proxy-like iterator in Club:

class Club {

struct iterator : list<Person>::iterator {
    explicit iterator(list<Person*>::iterator i) : ptr_(i) {}

    iterator(iterator const& i) : ptr_(i.ptr_) {}

    iterator& operator=(iterator i) {
        using std::swap;
        swap(this->ptr_, i.ptr_);
        return *this;

    reference operator*() const {
        return **ptr_;

    pointer operator->() const {
        return &(operator*());

    iterator& operator++() {
        return *this;

    iterator operator++(int) {
        iterator tmp(*this);
        return tmp;

    /* operator-- omitted */

    friend bool operator==(iterator x, iterator y) {
        return x.ptr_ == y.ptr_;

    friend bool operator!=(iterator x, iterator y) {
        return !(x == y);

    list<Person*>::iterator ptr_;
list<Person*> officers;

iterator begin() {
    return iterator(officers.begin());

iterator end() {
    return iterator(officers.end());

So that you can use

     ostream_iterator<Person>(cout, "\n"));

To print the Club. Cool?

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