// Create a PriorityQueue that holds any object that
// implements an IPrioritizable interface.
static void Main(string[] args)
{
// Set the number of priority levels we're using.
int numPriorities = 5;
// Create a priority queue.
// Note that we instantiate the PQ for IPrioritizable objects!
PriorityQueue <IPrioritizable> pq =
new PriorityQueue <IPrioritizable>(numPriorities);
// Create a random number (0 - 50) of random
// packages and parcels; add them to the priority queue.
IPrioritizable pack;
PackageFactory fact = new PackageFactory();
// We want a random number less than 50.
Random rand = new Random();
// Get a random int from 0 - 50.
int numToCreate = rand.Next(50);
Trace.WriteLine("TRACE: Creating 50 packages");
Console.WriteLine("Receiving packages:");
for (int i = 0; i < numToCreate; i++)
{
// Generate a random package.
pack = fact.CreatePackage(numPriorities);
Trace.WriteLine(
String.Format("\received a {0}", pack.ToString()));
Console.WriteLine(
"\tReceived package {0}: a {1}", i, pack.ToString());
// Add it to the priority queue.
pq.Enqueue(pack);
}
// See what we got.
Trace.WriteLine(
String.Format("Received {0} packages", pq.Count));
Console.WriteLine("Packages received: {0}", pq.Count);
Console.WriteLine("\tList:");
// Display packages with priorities and ToAddresses.
// Uses new PriorityQueue.GetEnumerator()
foreach (IPrioritizable ip in pq)
{
if (ip != null)
{
Console.WriteLine("\t\ta {0} sent to {1}",
ip.ToString(), ((IPackage)ip).ToAddress);
// The parentheses above ensure that we first
// extract the item, then convert it to IPackage,
// and finally call ToAddress(), which would be
// illegal this way: (IPackage)ip.ToAddress()
}
}
// "Ship" all packages.
int totalShipped = 0;
Trace.WriteLine("TRACE: Before shipping, count = " + pq.Count);
Console.WriteLine("\tshipping all packages (in priority order, of course):");
int numToShip = pq.Count;
// Dequeue the correct number of packages.
// Another way to iterate the PriorityQueue.
for (int i = 0; i < numToShip; i++)
{
IPrioritizable ipack = pq.Dequeue();
if (ipack != null)
{
// Note you can call ToString() on any object, don't
// need a cast for this one.
Console.WriteLine("\tShipped a {0}", ipack.ToString());
++totalShipped;
}
Trace.WriteLine(
String.Format("TRACE: Main() with {0} items to go", pq.Count));
}
// See how many we "shipped."
Console.WriteLine("Shipped {0} packages", totalShipped);
Trace.WriteLine(
String.Format("TRACE: Terminating after shipping {0} packages",
totalShipped));
// Wait for user to acknowledge the results.
Console.WriteLine("Press Enter to terminate...");
Console.Read();
}
public int CompareTo(IPrioritizable other)
{
return(Priority.CompareTo(other?.Priority ?? int.MaxValue));
}
