是否可以制作一个指向struct（节点）的指针数组？

Question

So I'm trying to make a prefix tree, but I'm not sure if this would cause some logical error of some sort?

typedef struct TreeTag
{
    char letter;
    struct TreeTag *links[26]; /* Is this advisable? */
    int fullword;
    int linknum;
}TreeNode;

Answer 1

Yes, array of pointers to struct node is allowed

If you do this:

struct node * p; //it's allowed

so there is no problem to declare array of pointers.

When you need the more than one pointers to the same struct you do this

struct node * left;
 strcut node * right;

so why can't you do this

struct node *child[2];

Similarly struct node *p[26] is also possible but everything depends on your requirement and implementation.

One requirement , As I think think of d-ary tree (where each node has d nodes) And you want to directly nevigate to it's children from parent node.

so struct node *child[d] is legal (where d is #defined )

Answer 2

That's fine. You can use pointers to the struct inside the struct.

The struct is considered declared, but not defined, at the point you declare the member, and pointers to declared, but not yet defined types, are common. How would you, for example, be able to define the nodes in a binary tree or a linked list otherwise? For a list, you would normally do something like

typedef struct ListItem {
   struct ListItem * next;
   SomeType data;
} ListItem;