#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

struct T {
  bool a;
  uint8_t b;
};

enum Shape_Tag {
  Circle,
  Rectangle,
};

struct Circle_Body {
  double radius;
};

struct Rectangle_Body {
  double width;
  double height;
};

struct Shape {
  enum Shape_Tag tag;
  union {
    struct Circle_Body circle;
    struct Rectangle_Body rectangle;
  } body;
};

enum BTree_Tag {
  Leaf,
  Fork,
};

struct Leaf_Body {
  int64_t value;
};

struct Fork_Body {
  const struct BTree *left;
  const struct BTree *right;
};

struct BTree {
  enum BTree_Tag tag;
  union {
    struct Leaf_Body leaf;
    struct Fork_Body fork;
  } body;
};

void hello(const char *c);

void hello_struct(struct T t);

void hello_shape(struct Shape s);

__attribute__((const)) int64_t add(int64_t a, int64_t b);

int64_t sum_tree(struct BTree t);