I have a question in C language typeef and function pointer.

Hello, I'm asking you a question because there are parts in grammar that I don't understand well while studying the data structure.

typedef void VisitFuncPtr(BTData data);

void InorderTraverse (BTreeNode* bt, VisitFincPtraction) // Lieutenant Tour
{
    If (bt == NULL) // If bt is NULL, recursive escape
        return;

    InorderTraverse (bt->left, action); // Stage 1 Tour of the left subtree
    action(bt->data); // Step 2 root node visit
    InorderTraverse (bt->right, action); // Stage 3 Tour of the right subtree

}

I think I only need a part of the sauce, so I'll put a part of the sauce on it, but if you need the whole sauce, I'll edit it and upload it. In the book, there was a part where a function pointer was used in a source that traveled and visited nodes while studying binary trees. You use a function pointer, but you use typedef void VisitFuncPtr(BTData data); like the source above. It was unfamiliar because it was my first time using a function pointer as a typeef, but I read it because I thought it was different from normal typeef When I first saw this sentence, what was it? It's not the shape of the function pointer I know I thought so, but I kept reading it because I thought something would come out if I looked at the back. However, I don't understand well even if I read it, so I leave a message here.

If it's the shape of the function pointer that I studied when I studied the basics of C language, void (*VisitFuncPtr) (BTData); It should have looked like this. Return type is void and pointer variable? The name is VisitFuncPtr, and the parameter data type is a function pointer with one BTData. Like this. And according to the grammar of the typeef that I studied, the nickname at the end? There should be the same thing, but there isn't. Like writing int as ABC in typedef int ABC.

But it's embarrassing to write it like that and call it a function pointer.

Even in the following InorderTraverse (BTreeNode* bt, VisitFincPtraction) function, VisitFuncPtraction has no idea how to interpret this parameter.Is action the variable name of VisitFuncPtr? If so, VisitFuncPtr means type, but VisitFuncptr is a function pointer name, not type, but I'm confused The action(bt->data); part of the body is also blocked in the parameter, so it is confusing because it is not accurate to grasp something.

It seems like the grammar I usually knew, but it comes out a little different, so I don't understand it well I'm asking you a question because I don't know it, but I'd appreciate it if you could answer it.