static async Task Main(string[] args)
{
Adam adam = Adam.GetInstance();
Adam anotherAdam = Adam.GetInstance();
Console.WriteLine(adam is Adam);
Console.WriteLine(ReferenceEquals(adam, anotherAdam));
Console.ReadKey();
}
public static Eve GetInstance(Adam adam)
{
if (adam is null)
{
throw new ArgumentNullException("Eve is created from the rib of Adam");
}
else
{
return(_eve ?? (_eve = new Eve()));
}
}
public static Adam GetInstance() => _adam ?? (_adam = new Adam());