Safe Sensor nullptr Check

Question

Problem: Safe Sensor nullptr Check. Solve this hands-on electronics task on EWskills.

Accepted Answer

#include 
using namespace std;

int main() {
    int flag;
    cin >> flag;

    int* sensorPtr = nullptr;

    if (flag == 1) {
        sensorPtr = new int;
        cin >> *sensorPtr;
    }

    if (sensorPtr == nullptr) {
        cout << "NO SENSOR";
    } else {
        cout << *sensorPtr;
    }

    delete sensorPtr;
    return 0;
}

Explanation & Logic Summary:

sensorPtr starts as nullptr to indicate absence of hardware
Memory is allocated only when the sensor is reported as connected
A nullptr check prevents unsafe dereferencing
delete on a null pointer is safe and deterministic

Firmware Relevance & Real-World Context:

Optional peripherals are common in embedded systems
nullptr cleanly represents unavailable hardware
Prevents null dereference crashes (critical firmware faults)
Common patterns include:
- HAL optional drivers
- RTOS object handles
- Callback and resource pointers

37. Safe Sensor nullptr Check