Issues with my custom "Circular Singly Linked List" Iterator

[dense compass]

Hello, I'm making a custom Circular Singly Linked List and I'm having issue making the custom iterator.
If I want the loop the go from the head to the tail : the begin() should be an Iterator( m_pHead ) and the end() an Iterator( m_pTail->m_pNext ) because I don't want to stop when the iterator reaches the tail but when it reaches the node after the tail (so that the code in the "for" is also applied to the tail).
The issue is that m_pHead == m_pTail->m_pNext so the loop doesn't event start because the iterator is already equal to m_pTail->mèpNext

[arctic spear]

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[dense compass]

Does anyone have an idea ?

[quasi kiln]

Your end iterator should be a sentinel iterator, not iterator(tail ->next)

[dense compass]

sentinel ?

[quasi kiln]

Special value iterator. Like sometimes -1 is used as a sentinel value to indicate an index that doesn't exist, e.g. for finding a value in a vector

[dense compass]

but then my loop iterator is never going to be the end iterator if it's not a value that is in the list ?

like the

template <typename T>
typename ITERATOR& ITERATOR::operator++()
{
    m_pNode = m_pNode->m_pNext;
    return *this;
}

it only select the next node

how is it going to be able to compare ?

[quasi kiln]

You need to figure out how to make that not happen by returning a sentinel iterator instead of the begin iterator

[dense compass]

I'm sorry but I tried to search online how to make a sentinel, examples of existing ones but I really have no idea how to do it...

[quasi kiln]

Make m_pNode null, for example

[tribal kindle]

basically your tail->next shouldnt be the head, it should be some special node

and that special node can point back to the head if you want

then you can use that special "sentinel" node to mark that you reached the end

[dense compass]

oh alr

ooooooh

ok I'll try it

[dense compass]

alr so it worked perfectly by adding the "sentinel" Node between tail and head

but I'm gonna try something else that I though of because I don't really like the fact that I have to take more memory in my list simply for an iterator that is not even necessary (only useful for the for ( auto it : list ) in my case)

but thanks !

😄

!solve