29. Safe Sensor nullptr Check

Your firmware supports an optional sensor represented by a pointer.

• If no sensor is connected, the pointer must remain nullptr
• If a sensor is connected, memory must be dynamically allocated and used to store the sensor reading

Based on input, safely handle the pointer and print the correct output.

Steps:

1. Read an integer flag
2. Behavior based on flag:
   • 0 → no sensor connected → pointer remains nullptr
   • 1 → sensor connected → dynamically allocate memory and read the sensor value
   • Any other value → treat as no sensor connected
3. Output:
   • Print "NO SENSOR" if the pointer is nullptr
   • Otherwise, print the stored sensor value
4. Free allocated memory (if any) before exiting

Input Format:

• First integer: flag
• If flag == 1, a second integer follows representing the sensor reading

Output Format:

• "NO SENSOR" (exact, uppercase, no extra spaces), or
• The integer sensor value

Example 1

Input:

0

Output:

NO SENSOR

Example 2

Input:

1 35

Output:

35

Constraints:

• Use nullptr to represent a missing sensor
• Do not dereference a null pointer
• Sensor readings may be negative, zero, or positive integers
• Invalid flag values must not cause undefined behavior