/* stack.h
 *
 * University of Edinburgh
 * 
 * Stack containing an array of doubles
 */

typedef struct stack_node_tag stack_node;
typedef struct stack_tag stack;

struct stack_node_tag {
  double     data[2];
  stack_node *next;
};

struct stack_tag {
  stack_node     *top;
};


stack *new_stack();
void free_stack(stack *);

void    push(double *, stack *);
double *pop (stack *);

int is_empty (stack *);