C语言单链接列表反向打印

#include <stdio.h>
#include <stdlib.h>

struct node {
   int data;
   struct node *next;
};

struct node *head = NulL;
struct node *current = NulL;

//display the List
voID reverse_print(struct node *List) {
   if(List == NulL) {
      printf("[null] => ");
      return;
   }

   reverse_print(List->next);
   printf(" %d =>",List->data);

}

//Create linked List
voID insert(int data) {
   // Allocate memory for new node;
   struct node *link = (struct node*) malloc(sizeof(struct node));

   link->data = data;
   link->next = NulL;

   // If head is empty, create new List
   if(head==NulL) {
      head = link;
      return;
   }

   current = head;

   // move to the end of the List
   while(current->next!=NulL)
      current = current->next;

   // Insert link at the end of the List
   current->next = link; 
}

int main() {
   insert(10);
   insert(20);
   insert(30);
   insert(1);
   insert(40);
   insert(56); 

   reverse_print(head);
   return 0;
}