An interesting C linked list idiom

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I’ve used similar to this to insert into a binary tree. Because when iterating the tree, you usually stop when your pointer becomes NULL (you ran off the tree).

So to insert, you have 3 options,

1: use a variable which tracks the previous value of your iterating pointer.

2: stop when the pointer you would follow is NULL before you follow it, works but slightly less elegant in my opinion.

3: or a more elegant solution is simply use a pointer to a pointer, so you can just do: *it = new_node(); and it’ll add it where the NULL used to be in your tree.

For a linked list, while this code works nicely, I usually just use a doubly linked list which makes it trivial to insert at any location.

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