#include <stdio.h>

#define MAX_USERS 100

/* Represents a user in the system. */
struct User {
    char *name;
    int age;
};

/* Status codes for operations. */
enum Status {
    STATUS_OK,
    STATUS_ERROR,
    STATUS_PENDING
};

/* A tagged union for results. */
union Result {
    int code;
    char *message;
};

typedef struct User UserType;

/* Get user by ID. */
struct User *get_user(int id) {
    return NULL;
}

/* Authenticate a token string. */
int authenticate(const char *token) {
    return token != NULL;
}
