Custom Data Structure Design

DeviceType Enum

typedef enum {
    TEMPERATURE_SENSOR,
    MOTION_DETECTOR,
    LIGHT,
    LOCK
} DeviceType;

DeviceState Enum

typedef enum {
    OFFLINE,
    IDLE,
    ACTIVE,
    ERROR
} DeviceState;

SensorData Union

typedef union {
    struct { float temperature; int humidity; } temp_data;
    struct { int motion_detected; int sensitivity; } motion_data;
    struct { int brightness; int color_temp; } light_data;
    struct { int locked; int battery_level; } lock_data;
} SensorData;

HardwareRegister with Bit Fields

typedef struct {
    unsigned int power_on : 1;
    unsigned int alert_enabled : 1;
    unsigned int auto_mode : 1;
    unsigned int debug_mode : 1;
    unsigned int reserved : 4;
} HardwareRegister;

create_device()

Device* create_device(int device_id, DeviceType type)

• Allocate device with malloc()
• Initialize ID, type, and state to OFFLINE
• Initialize registers to all zeros
• Return pointer to allocated device

update_temperature()

void update_temperature(Device* device, float temp, int humidity)

• Verify device type is TEMPERATURE_SENSOR
• Update union with temperature and humidity
• Set device state to ACTIVE
• Update last_update timestamp

update_motion()

void update_motion(Device* device, int detected)

• Verify device type is MOTION_DETECTOR
• Update union with motion detection status
• Set state to ACTIVE if motion detected, IDLE otherwise
• Update last_update timestamp

control_light()

void control_light(Device* device, int brightness, int color_temp)

• Verify device type is LIGHT
• Validate brightness (0-255) and color_temp (2700-6500)
• Update union with values if valid
• Set state to ACTIVE if brightness > 0
• Update last_update timestamp

control_lock()

void control_lock(Device* device, int lock_state)

• Verify device type is LOCK
• Update union with lock state (0=unlocked, 1=locked)
• Check battery level and set ERROR state if < 10%
• Update last_update timestamp

set_register_bit()

void set_register_bit(Device* device, int bit_position, int value)

• Manipulate hardware register bit fields
• bit_position: 0=power_on, 1=alert_enabled, 2=auto_mode, 3=debug_mode
• Validate bit_position (0-3) and value (0-1)
• Use bitwise operations for manipulation

display_device_info()

void display_device_info(Device* device)

• Print device ID, type, and state
• Print sensor data based on device type
• Print register status (binary representation)
• Print last_update timestamp
• Use formatted output (printf with proper formatting)

free_device()

void free_device(Device* device)

• Properly deallocate memory using free()
• Set pointer to NULL after freeing (if passing by reference)
• Include safety check for NULL pointer