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

#define PLUS 0
#define TIMES 1
#define CONST 2
#define VAR 3

struct polynomial {
  int type; // PLUS, TIMES, CONST ou VAR
  int value; // Si CONST, la valeur de l'entier. Si VAR, le numéro de la variable
  struct polynomial *p1, *p2; // Si PLUS ou TIMES, les arguments
};
typedef struct polynomial polynomial;

// Évalue un polynôme. v[i] correspond à la valeur de la variable i
int eval(polynomial *p, int v[]) {
  switch (p->type) {
  case CONST:
    return p->value;
  case VAR:
    return v[p->value];
  case PLUS:
    return eval(p->p1, v)+eval(p->p2, v);
  case TIMES:
    return eval(p->p1, v)*eval(p->p2, v);
  default:
    return 0;
  }
}

polynomial *create_node(int type, int value, polynomial *p1, polynomial *p2) {
  polynomial *p = (polynomial *) malloc(sizeof(polynomial));
  p->type = type;
  p->value = value;
  p->p1 = p1;
  p->p2 = p2;
}

int main() {
  polynomial *p = create_node(PLUS, 0,
			      create_node(VAR, 0, NULL, NULL),
			      create_node(VAR, 1, NULL, NULL));
  return 0;
}