/* 
* Code example for CP264 Data Structures II
* linked list design implementation
* HBF 
*/
#include "llist.h"

/**
 * Display linked list.
 * @param start Pointer to the first node of linked list.
 */
void display(node *start) {
  if (start == NULL) printf("empty\n");
  else {
    node *np = start;
    while(start != NULL) {
      printf("data:%d, address:%d\n", start->data, start);
      start = start->next;
    }
  }
}

node *new_node(int num) {
  node *np = (node *) malloc(sizeof(node));
  if (np == NULL) return NULL;
  np->data = num;
  np->next = NULL;  
  return np;
}

int get_data(node *np) {
	return np->data;
}

void set_data(node *np, int num) {
	np->data = num;
}

void insert_beg(node **startp, int num) {
  node* np = (node *)malloc(sizeof(node));
  if (np == NULL) {printf("malloc fails"); return;}
  np->data = num;
  np->next = NULL; 

  node *temp = *startp;
  np->next = temp;
  *startp = np;
}

void insert_end(node **startp, int num) {
  node *np = *startp;
  node *prev = NULL;

  while(np != NULL){
    prev = np;
    np = np->next;
  }
  np = (node *)malloc(sizeof(node));
  np->data = num;
  np->next = NULL;  
  if (prev == NULL)
    *startp = np;
  else 
    prev->next = np;
}

int delete(node **startp, int num) {
  node *np = *startp;
  node *prev = NULL;

  while ( (np != NULL) && (np->data != num )) {
    prev = np;
    np = np->next;
  } 
   
  if (np == NULL) {
    return 0;
  } else {
    if (prev == NULL)
      *startp = np->next;
    else
      prev->next = np->next;
    free(np);
    return 1;
  } 
}
     
node *search(node *start, int num) {
  node *np = start;
  while(np != NULL && np->data != num)
    np = np->next;
  if (np->data == num) return np; //found
  else return NULL; //not found
}

int length(node *start) {
  int len = 0;
  while(start != NULL) {
    len++;
    start = start->next;
  }
  return len;
}

void clean(node **startp) {
  node *np = *startp, *temp;
  while (np != NULL) { 
	temp = np; 
	np = np -> next;
	free(temp);
  }
  *startp = NULL;
}