var monitor = new VitalsMonitor();
monitor.CriticalVitalsDetected += (sender, e) =>
{
    Console.WriteLine($"  *** CRITICAL ALERT: HR is {e.HeartRate}, SpO2 is {e.SpO2} ***");
};
Console.WriteLine("Starting patient monitoring...\n");
monitor.RecordVitals(75, 98);
monitor.RecordVitals(80, 97);
monitor.RecordVitals(130, 85);
monitor.RecordVitals(45, 95);
// --- Class Definitions ---
public class VitalsArgs : EventArgs
{
    public int HeartRate { get; }
    public int SpO2 { get; }
    public VitalsArgs(int heartRate, int spO2)
    {
        HeartRate = heartRate;
        SpO2 = spO2;
    }
}
public class VitalsMonitor
{
    public event EventHandler<VitalsArgs>? CriticalVitalsDetected;
    public void RecordVitals(int heartRate, int oxygenLevel)
    {
        Console.WriteLine($"Reading - HR: {heartRate}, SpO2: {oxygenLevel}");
        
        if (heartRate < 50 || heartRate > 120 || oxygenLevel < 90)
        {
            CriticalVitalsDetected?.Invoke(this, new VitalsArgs(heartRate, oxygenLevel));
        }
    }
}