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

typedef struct T {
  bool a;
  uint8_t b;
} T;

typedef uint8_t Shape_Tag;
#define Circle  0
#define Rectangle  1

typedef struct Circle_Body {
  double radius;
} Circle_Body;

typedef struct Rectangle_Body {
  double width;
  double height;
} Rectangle_Body;

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

void hello(const char *c);

void hello_struct(struct T t);

void hello_shape(struct Shape s);