Linked Lists in C

Code:

int compare(struct integer *p, struct integer *q)
{
    
    int j;
    
    while  (p != NULL){
           if(q==NULL){
             return 1;}
             else if (q!=NULL){
                          if (p>q){
                                   j=1;}
                          else if (p<q){
                                   j= -1;}
                          else if (p==q){
                                   j= 0;}
                                   }
             p= p->next;
             q= q->next;
            
            
             }
            
            
return (j);            
}

returns, for the numbers above, -1, -1, 1, -1, -1. Which is wrong for the first and last one. Whereas

Code:

int compare(struct integer *p, struct integer *q)
{
    int c;
    
  if (p == NULL) return -1;
  if (q == NULL) return 1;
  // or vice versa
  if (p->next != NULL && q -> next != NULL) {
   c = compare(p->next, q->next);
   if (c == 0) {
    if (p > q) return 1;
    if (q > p) return -1;
    else return 0;
   }
   else return c;
  }
  else return 0;
}

returns all -1s, which is wrong for the first, third, and last ones. The only thing i changed in your code was i added a semicolon after c = compare(p->next, q->next) since it wouldnt let me compile, and capitalized the null to NULL. And I declared c, since it was undeclared.