Implementing GEO Fence Function for Drones in C++

This is an example of how you might implement a GEO fence function for drones in C++:

```#include <iostream>
#include <cstdlib>
#include <string>

#define MAX_LATITUDE 90  // Maximum allowed latitude coordinate
#define MIN_LATITUDE -90 // Minimum allowed latitude coordinate
#define MAX_LONGITUDE 180 // Maximum allowed longitude coordinate
#define MIN_LONGITUDE -180 // Minimum allowed longitude coordinate

struct GPSCoordinate {
double latitude;
double longitude;
};

// Returns true if the GPS coordinate is within the defined fence boundaries, false otherwise
bool withinFenceBoundaries(GPSCoordinate coord) {
if (coord.latitude > MAX_LATITUDE || coord.latitude < MIN_LATITUDE ||
coord.longitude > MAX_LONGITUDE || coord.longitude < MIN_LONGITUDE) {
return false;
}
return true;
}

int main() {
GPSCoordinate currentLocation;

// Get current GPS coordinates from drone
// (assume this is done using some other function or hardware)
currentLocation.latitude = 50.0;
currentLocation.longitude = 50.0;

if (withinFenceBoundaries(currentLocation)) {
std::cout << "Drone is within fence boundaries. Continuing normal flight operations." << std::endl;
} else {
std::cout << "Drone is outside of fence boundaries. Initiating emergency landing procedures." << std::endl;
}

return 0;
}

```

This code defines a GPSCoordinate struct to represent a GPS coordinate, and a function called withinFenceBoundaries() that takes a GPSCoordinate as an argument and returns a bool indicating whether the coordinate is within the defined fence boundaries.

In the main function, the current GPS coordinates are retrieved from the drone (assumed to be done using some other function or hardware). Then, the withinFenceBoundaries() function is called to determine whether the drone is within the fence boundaries. If it is, the drone continues normal flight operations. If it is not, the drone initiates emergency landing procedures.

This is just one example of how GEO fence mode could be implemented in C++ for drones. The specific implementation will depend on the capabilities and resources available on the drone, as well as the specific requirements of the application.