#define NAMELENGTH 20
#include <string.h>
#include <stdio.h>

typedef char name_t[NAMELENGTH];
typedef enum {FALSE=0, TRUE} boolean;
typedef enum {DOG=7, FISH=1, CAT} pet_kind;

typedef struct {
	int age;
	name_t name;
	float weight;
	int num_bones;
	} dog;

typedef struct {
	name_t color;
	boolean salt_water;
	} fish;

typedef struct {
	int age;
	name_t name;
	float weight;
	} cat;
	
typedef struct {
	pet_kind kind;
	union { dog mydog;
			  fish myfish;
			  cat mycat;
			} info;
	} pet;


int main () {
	pet rover;
	
	rover.kind = DOG;
	rover.info.mydog.age = 9;
	strcpy (rover.info.mydog.name, "J.D.'s Beach Bum II");
	rover.info.mydog.num_bones = 4;
	rover.info.myfish.salt_water = TRUE; /* still legal, but changes the dog's name! */
	
	switch (rover.kind) {
		case (DOG) : {
			printf ("%s has %d bones.", rover.info.mydog.name, rover.info.mydog.num_bones);
			break;
			}
		case (FISH) : {
			printf ("Rover is %s", rover.info.myfish.color);
			break;
			}
		case (CAT) : {
			printf ("Rover is %d years old.", rover.info.mycat.age);
			break;
			}
		}
	/* rover.mycat.num_bones = 5; doesn't compile */
	
	rover.kind = TRUE; /* presto-change-o, rover is now a fish! */
	/* because the numeric value of TRUE happens to equal that of FISH */
	
	return 0;
	}