C++ Primer, Fifth Edition

9.3.4. Specialized forward_list Operations

To understand why forward_list has special versions of the operations to add and remove elements, consider what must happen when we remove an element from a singly linked list. As illustrated in Figure 9.1, removing an element changes the links in the sequence. In this case, removing elem₃ changes elem₂; elem₂ had pointed to elem₃, but after we remove elem₃, elem₂ points to elem₄.

Figure 9.1. forward_list Specialized Operations

When we add or remove an element, the element before the one we added or ...