Question

Considering the following c code:

typedef struct ELE *tree_ptr

struct ELE {
   long val;
   tree_ptr left;
   tree_ptr right;
};

I believe ELE encapsulates a single node of a binary tree. Each node has some 32-bit value(val), a pointer to a left node, and a pointer to a right node.

Can someone confirm that my interpretation is correct?

Also, is ELE just an arbitrary variable name or some convention used to name a struct?

edit:

What if there was a c program that generated the following 3 lines of assembly code:

movq     %rbx, -24(%rsp)
movq     %rbp, -16(%rsp)
movq     %r12, -8(%rsp)

Are these 3 lines making room for the 3 elements of the struct on the stack?

Answer 1

That would most likely be ELEment, one element of the collection.

A few other points to consider:

1. Your typedef needs a semicolon at the end.
2. The C standard doesn’t guarantee that long integers are 32 bits.
3. The type tree_ptr indicates that it probably is a binary tree but all you know for sure is that it’s a structure containing a long and the two pointers to the same type as the structure. It may well be a doubly-linked list if the coder that put it together was deranged or sadistic enough 🙂