/**************************************
 * stack.c
 *
 * Programme d'exemple implémentant un stack comme structure
 * chaînée
 *
 **************************************/

#include <stdio.h>
#include <stdlib.h>

typedef struct fraction_t {
  int num;
  int den;
} fraction;

///AAA
typedef struct node_t
{
  struct fraction_t *data;
  struct node_t *next;
} node;

struct node_t *stack; // sommet de la pile

// ajoute un élément au sommet de la pile
void push(struct fraction_t *f)
{
  struct node_t *n;
  n=(struct node_t *)malloc(sizeof(struct node_t));
  if(n==NULL)
    exit(EXIT_FAILURE);
  n->data = f;
  n->next = stack;
  stack = n;
}
// retire l'élément au sommet de la pile
struct fraction_t * pop()
{
  if(stack==NULL)
    return NULL;
  // else
  struct fraction_t *r;
  struct node_t *removed=stack;
  r=stack->data;
  stack=stack->next;
  free(removed);
  return (r);
}

///BBB

// affiche le contenu de la pile
void display()
{
  struct node_t *t;
  t = stack;
  while(t!=NULL) {
    if(t->data!=NULL) {
      printf("Item at addr %p  :  Fraction %d/%d   Next %p\n",t,t->data->num,t->data->den,t->next);
    }
    else {
      printf("Bas du stack %p\n",t);
    }
    t=t->next;
  }
}

// exemple
int main(int argc, char *argv[]) {

  struct fraction_t demi={1,2};
  struct fraction_t tiers={1,3};
  struct fraction_t quart={1,4};
  struct fraction_t zero={0,1};

  // initialisation
  stack = (struct node_t *)malloc(sizeof(struct node_t));
  stack->next=NULL;
  stack->data=NULL;

  display();
  push(&zero);
  display();
  push(&demi);
  push(&tiers);
  push(&quart);
  display();

  struct fraction_t *f=pop();
  if(f!=NULL)
    printf("Popped : %d/%d\n",f->num,f->den);

  return(EXIT_SUCCESS);
}
///CCC