GESTION DES LISTE CHAINÉES

// Auteur : nicof31@everyday.com
// But    : - Montrer comment fonctionnent les listes simplement chainees
//         - Offrir un set de fonctions reutilisables ou facilement adaptables pour d'autres programmes



#include <stdio.h>
#include <stdlib.h>
#include <malloc.h> // a enlever selon le compilateur utilise (necessaire sous VC++)


///////////////////////////////////
// Definition d'un maillon de liste
///////////////////////////////////
typedef struct tag_link
{
  int              data;
  struct tag_link  *next;
} LINK;


//////////////////////
// Initialise la liste
//////////////////////
void Init(LINK *list)
{
  list->next = NULL;
}


////////////////////////////////////
// Ajoute un maillon en fin de liste
////////////////////////////////////
void Add(LINK *list, int data)
{
  LINK  *next_link;


  next_link = list;
  while(next_link->next)
  {
    next_link = next_link->next;
  }

  next_link->next = malloc(sizeof(LINK));

  (next_link->next)->data = data;
  (next_link->next)->next = NULL;
}


//////////////////////////////////
// Insere un maillon dans la liste
//////////////////////////////////
int Insert(LINK *list, int pos, int data)
{
  LINK  *next_link, *sav_link;
  int   i;


  next_link = list;
  i = 0;
  while(next_link->next && i < pos-1)
  {
    next_link = next_link->next;
    i++;
  }

  if(i == pos-1)
  {
    sav_link = next_link->next;
    next_link->next = malloc(sizeof(LINK));
    (next_link->next)->data = data;
    (next_link->next)->next = sav_link;

    return 1;
  }
  else
  {
    return 0;
  }
}


/////////////////////////////////
// Detruit un maillon de la liste
/////////////////////////////////
int Delete(LINK *list, int pos)
{
  LINK  *next_link, *sav_link;
  int   i;
  
  
  next_link = list;
  i = 0;
  while(next_link->next && i < pos-1)
  {
    next_link = next_link->next;
    i++;
  }

  if(i == pos-1)
  {
    sav_link = (next_link->next)->next;
    free(next_link->next);
    next_link->next = sav_link;

    return 1;
  }
  else
  {
    return 0;
  }
}


/////////////////////////////////////////
// Libere la memoire allouee par la liste
/////////////////////////////////////////
void Free(LINK *list)
{
  LINK  *next_link, *next2_link;

  
  next2_link = list->next;

  while(next2_link)
  {
    next_link = next2_link;
    next2_link = next_link->next;
    free(next_link);
  }

  list->next = NULL;
}


//////////////////////////////////////////////////
// Affiche le nb de maillons que contient la liste
//////////////////////////////////////////////////
int Count(LINK *list)
{
  LINK  *next_link;
  int   i;


  next_link = list;
  i = 0;
  while(next_link->next)
  {
    next_link = next_link->next;
    i++;
  }

  return i;
}


///////////////////////////////////
// Affiche les elements de la liste
///////////////////////////////////
void Print(LINK *list)
{
  LINK  *next_link;
  int   i;


  next_link = list;
  i = 0;
  while(next_link->next)
  {
    next_link = next_link->next;
    printf("Maillon %d : %d\n", ++i, next_link->data);
  }

  printf("\n");
}


//////////////////////
// Fonction principale
//////////////////////
int main(void)
{
  LINK  list;
  int   i;


  // Initialisation de la liste
  Init(&list);

  // On remplit la liste (ajouts d'elements en fin de liste)
  for(i = 0; i < 5; i++)
  {
    Add(&list, 2*i);
  }
  Print(&list);

  // Insertion d'un element en milieu de liste
  Insert(&list, 4, -20);
  Print(&list);

  // Suppression d'un element en milieu de liste
  Delete(&list, 2);
  Print(&list);

  // Compte et affiche le nombre d'elements que contient la liste
  printf("La liste comporte %d elements\n", Count(&list));

  // Libere la memoire allouee pour les elements de la liste
  Free(&list);

  return 1;
}