// Define a service contract. 
[ServiceContract(Namespace="http://Microsoft.ServiceModel.Samples")]
public interface IQueueCalculator
{
    [OperationContract(IsOneWay=true)]
    void Add(double n1, double n2);
    [OperationContract(IsOneWay = true)]
    void Subtract(double n1, double n2);
    [OperationContract(IsOneWay = true)]
    void Multiply(double n1, double n2);
    [OperationContract(IsOneWay = true)]
    void Divide(double n1, double n2);
}

// Service class that implements the service contract.
// Added code to write output to the console window
public class CalculatorService : IQueueCalculator
{
    [OperationBehavior]
    public void Add(double n1, double n2)
    {
        double result = n1 + n2;
        Console.WriteLine("Received Add({0},{1}) - result: {2}", n1, n2, result);
    }

    [OperationBehavior]
    public void Subtract(double n1, double n2)
    {
        double result = n1 - n2;
        Console.WriteLine("Received Subtract({0},{1}) - result: {2}", n1, n2, result);
    }

    [OperationBehavior]
    public void Multiply(double n1, double n2)
    {
        double result = n1 * n2;
        Console.WriteLine("Received Multiply({0},{1}) - result: {2}", n1, n2, result);
    }

    [OperationBehavior]
    public void Divide(double n1, double n2)
    {
        double result = n1 / n2;
        Console.WriteLine("Received Divide({0},{1}) - result: {2}", n1, n2, result);
    }
}

// This is the hosting application. This code can appear directly in the service class as well.
class HostApp
{
    // Host the service within this EXE console application.
    public static void Main()
    {
        // Get MSMQ queue name from appsettings in configuration.
        string queueName = ConfigurationManager.AppSettings["queueName"];

        // Create the transacted MSMQ queue if necessary.
        if (!MessageQueue.Exists(queueName))
            MessageQueue.Create(queueName, true);

        // Get the base address that is used to listen for WS-MetaDataExchange requests.
        // This is useful to generate a proxy for the client.
        string baseAddress = ConfigurationManager.AppSettings["baseAddress"];

        // Create a ServiceHost for the CalculatorService type.
        using (ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService), new Uri(baseAddress)))
        {
            // Open the ServiceHostBase to create listeners and start listening for messages.
            serviceHost.Open();

            // The service can now be accessed.
            Console.WriteLine("The service is ready.");
            Console.WriteLine("Press <ENTER> to terminate service.");
            Console.WriteLine();
            Console.ReadLine();

            // Close the ServiceHostBase to shutdown the service.
            serviceHost.Close();
        }
    }
}