[Header File] Single Linked List Implementation

sll.h

/** Singly Linked List (include Sort Ascending) 
    insert, remove, add, count source code 
**/

#ifndef SLL_H
#define SLL_H

typedef ... data_t;

struct node
{
  data_t data;
  struct node *next;
} *root; // global varibale pointer ROOT

/* Treo them 1 node o cuoi danh sach */
void append(data_t NewData)
{
  struct node *tem, *right;
  
  tem = (struct node *)malloc(sizeof(struct node));
  tem->data = NewData;

  right = (struct node*)root; // chay tu dau
  while(right->next!=NULL)
    right = right->next; // chay den node cuoi cung
  
  right->next = tem;
  right = tem;
  right->next = NULL;
}

/* Them 1 node vao dau danh sach */
void add(data_t NewData)
{
  struct node *tem;

  tem = (struct node*)malloc(sizeof(struct node));
  tem->data = NewData;

  if(root==NULL) // list chua co 1 phan tu nao
    {
      root = tem;
      root->next = NULL;
    }
  else
    {
      tem->next = root;
      root = tem;
    }
}

/* Chen vao giua */
void addAfter(data_t NewData, int loc) // loc: location i want to add to
{
  int i;
  struct node *tem, *left, *right;

  right = root;
  for(i=1; i<loc; i++)
    {
      left = right;
      right = right->next;
    }

  tem = (struct node *)malloc(sizeof(struct node));
  tem->data = NewData;
  
  left->next = tem;
  left = tem;
  left->next = right;
}

void insert(data_t NewData)
{
  struct node *tem;

  tem = root;
  if(tem==NULL)
    {
      add(NewData);
    }
  else
    {
      int c=0;
      
      while(tem!=NULL)
	{
	  if(tem->data<NewData)
	    c++;
	  tem = tem->next;
	}

      if(c==0) // min (add dau)
	add(NewData);
      else if(c<count())
	addAfter(NewData,++c); // gia tri tam trung trung
      else
	append(NewData); // max (append cuoi)
    }
}

/* Dem so phan tu node */
int count() 
{
  struct node *n;
  int c=0;

  n = root;
  while(n!=NULL)
    {
      n = n->next;
      c++;
    }

  return c;
}

void display(struct node *r)
{
  r = root;
  if(r==NULL)
    {
      return;
    }

  while(r!=NULL)
    {
      printf("%d  ",r->data);
      r = r->next;
    }
  printf("\n");
}
  
int delete(data_t DeleteData)
{
  struct node *tem, *prev;

  tem = root;
  while(tem!=NULL)
    {
      if(tem->data==DeleteData)
	{
	  if(tem==root) // be careful with root (must be survived)
	    {
	      root = tem->next; 
	      free(tem);
	      return 1;
	    }
	  else
	    {
	      prev->next = tem->next;
	      free(tem);
	      return 1;
	    }
	}
      else
	{
	  prev = tem;
	  tem = tem->next;
	}
    }

  return 0;
}

/* Reverse list */
struct node* reverse()
{
  struct node *cur, *prev;
  cur = prev = NULL;

  while(root != NULL) {
    cur = root;
    root = root->next;
    cur->next = prev;
    prev = cur;
  }

  return prev;
}

#endif