Reversing a linked list

#include <stdio.h>
                                                                             
typedef struct node {
       int val;
       struct node *next;
} Node;
                                                                             
Node* reverse (Node* head) {
       Node* previous=NULL;
       Node* current=head;
       Node* follow=head->next;
       Node* tmp;
       if (head == NULL || follow == NULL)
               return head;
       while (follow->next != NULL) {
               tmp=follow;
               follow=follow->next;
               tmp->next=current;
               current->next=previous;
               previous=current;
               current=tmp;
       }
       follow->next=current;
        current->next=previous;
       return follow;
}
                                                                             
void printlist (Node* node) {
       if (node==NULL)
               return;
       printf ("%d ",node->val);
       printlist (node->next);
}
                                                                             
int main (int argc, char* argv[]) {
       Node a,b,c,d;
       Node *t;
       a.val=1;
       a.next=&b;
       b.val=2;
       b.next=&c;
       c.val=3;
       c.next=&d;
       d.val=4;
       d.next=NULL;
       printlist(&a);
       printlist(t);
       printf ("\n");
       return 0;
}