if (racine==NULL){
    racine = ptr_c;
    ptr_p = ptr_c;
}
else {
    switch (emplacement){
    case 'g':
        pile.push(ptr_p);
        ptr_p->ptrGauche = ptr_c;
        ptr_p = ptr_c;
        break;
    case 'd':
        if (sizeof(pile) != 0) {
            ptr_p = pile.top();
            pile.pop();
        }
        ptr_p->ptrDroit = ptr_c;
        ptr_p = ptr_c;
        break;
    }

    if (ptr_c->sorte == 'O') {
        emplacement = 'g';
        }
    else emplacement = 'd';

}