Thread: Confusing with pointer to structure...Please help me see the code

I'm reading through a data structure textbook. I'm doing the part of Linked list.
here's the code from the textbook:
I'm not clear with pointer.

what I'm confused is that the code created a pointer to the structure (*NodePtr)
Q1. Is NodePtr store the address of the structure??
Q2. Are top, np, last address of the structure??
Q3. here.....NodePtr makeNode(int);... does it returns an address of the structure which is np?? but following part np is used as a pointer??

Please help me... thank you guys...

Code:

#include <stdio.h>
#include <stdlib.h>
typedef struct node{
  int num;
  struct node* next;
}Node, *NodePtr;

main()
{
 void printlist(NodePtr);
 NodePtr makeNode(int);
 int n;
 NodePtr top, np, last;

 top = NULL;
 if(scan(%d, &n)!= 1) n=0;
 while(n!=0)
 {
  np= makeNode(n);
  if(top == NULL) top = np;
  else last -> next = np;
  last = np;
  if(scanf("%d", &n)!=1) n= 0;
  }

 printList(top);
}

NodePtr makeNode(int n)
{
   NodePtr np = (NodePtr)malloc(sizeof(Node));
   np -> num = n;
   np -> next = NULL;
   return np;
}

void printList(NodePtr np)
{
   while(np != NULL)
   {
     printf("%d\n", np->num);
     np = np->next;
   }
}

from Data Structures in C. by Noel Kalicharan. page60

Thank you for replying me!

Can I say these: Node and *NodePtr, these are a type of data which is struct node
so *NodePtr is the structure, NodePtr is the pointer to the structure, so does np, top and last

What is the difference between Node and *NodePtr?
when declare does it means NodePtr occupy a single cell that stores the address of the structure which is NULL/rubbish at that time
while system create a full struct Node space for Node? - I might expressing it in a confusing way - Am I thinking it in the right way??

I'm asking so many questions
so in the code

Code:

NodePtr makeNode(int n)
{
   NodePtr np = (NodePtr)malloc(sizeof(Node));
   np ->num = n;
   np ->next = NULL;
   return np;
}

why its not cast as (*NodePtr)? I'm so bad at pointers
like this

Code:

char* buffer;
buffer = (char*)buffer(sizeof(char));

Originally Posted by xz1014

Node are *NodePtr, these are a type of data which is struct node

No, refer to nonpuz's code snippet in post #2. Node is an alias for struct node; NodePtr is an alias for struct node* (i.e., pointer to struct node). The *NodePtr syntax that you see is just syntax for the typedef to declare that NodePtr is an alias for struct node*. By itself, *NodePtr has no meaning as NodePtr is a type, so you cannot apply the dereference operator to it.