With out creating the interface, we can also directly created the service by placing Contract in the implemented class.So why we create Interfaces in WCF.
[ServiceContract()]
public class SimpleCal
{
[OperationContract()]
public int Add(int num1, int num2)
{
return num1 + num2;
}
}
Update "Why do I want to avoid using an Interface ? What would be the advantage to use a class only ?"