/* Creation de liste chainée circulaire avec n cellules */

#include<stdio.h> 
#include<stdlib.h>
#include<assert.h>
typedef struct cell cell; 

struct cell {
  int n; 
  struct cell * s; 
  struct cell * p; 
};

cell * creerliste(int x) { 
  int i; 
  cell * debut; 
  cell * oldcell;
  cell * newcell; 
  debut = malloc(sizeof (cell)); 
  assert(debut); 
  printf("%d ", debut->n = 1); 
  debut->s = debut; 
  debut->p = debut; 
  oldcell  = debut; 
  for(i = 2; i <= x; i++) { 
    newcell = malloc(sizeof *newcell); 
    assert(newcell); 
    printf("%d ", newcell->n = i); 
    newcell->s = debut; 
    newcell->p = oldcell; 
    oldcell->s = newcell; 
    debut->p   = newcell; 
    oldcell = newcell; 
  } 
  putchar('\n'); 
  return debut; 
} 

void liberer(cell * debut) { 
  cell * avant = debut; 
  cell * adetruire = avant->s; 
  cell * apres = adetruire->s; 
  while(adetruire != avant) { 
    avant->s = apres; 
    apres->p = avant;  
    printf("liberer %d ",avant->n);  
    adetruire->s = NULL; 
    adetruire->p = NULL; 
    avant = apres; 
    adetruire = avant->s; 
    apres = adetruire->s; 
  } 
  putchar('\n'); 
} 

int main() { 
  cell * liste = creerliste(10); 
  liberer(liste); 
  if(liste != NULL) { 
  } 
  else {
    return EXIT_FAILURE; 
  } 
  return 0; 
}