How to Erase Elements from a C `std::list` Using Reverse Iterators?

Erasing List Elements Using Reverse Iterators

In C , the erase function in the std::list container expects an iterator parameter. However, you may encounter a situation where you need to remove an element using a reverse iterator (std::list::reverse_iterator).

Solution:

According to the C standard, the following relationship exists between a reverse iterator i and its base iterator i.base():

&*(reverse_iterator(i)) == &*(i - 1)

This means that the reverse iterator points to the element immediately after the element pointed to by its base iterator.

To erase an element using a reverse iterator, you need to apply an offset to obtain the base iterator:

m_CursorStack.erase(--(i.base()));

This expression effectively decrements the base iterator by one, thereby pointing to the element to be erased.

Additional Solutions (C 11 and Later):

• Using std::next:

m_CursorStack.erase(std::next(i).base());

• Advancing the reverse iterator:

std::advance(i, 1);
m_CursorStack.erase(i.base());

These solutions are more concise and clearer than the original approach. Choose the one that best suits your requirements.

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