out vs ref

1A.  Difference between out and ref parameters?

• ref and out both are used for passing parameters by reference instead of value.

• You need to initialize the variable before passing in the case of ref.               

• In C# a variable must be initialized before it is used even in case of pass by value.

• To give an extra advantage to reference parameters, out is introduced where we don't need to initialize. 

• One more difference between ref and out is that in out u need to assign the value inside the function before returning otherwise it will give a compilation error. But in the case of ref, there is no such restriction.

•  Code reusability and hence less code.

•  Type safety and hence we can resolve run time exceptions in compile-time only.

•   no Typecasting and hence better performance.

        public static void  main 

       {

               int i = 100;   // Initialized before passing

              Add(ref i );

             Console.Writeline(i);

       }

       static void Add(ref int i)

       {

              i = i + 10;

       }

       public static void  main 

       {

               int i ;   // no need to initialize before passing

              Add(out i );

             Console.Writeline(i);

       }

       static void Add(out int i)

       {

              i = i + 10;

       }

1B.  Difference between the object as parameter and ref parameters?

If we use the ref keyword for the object, then it is going to create a new object and return that object.

Here if you write Console.WriteLine(test.Name);

it is going to return Director.

Now remove ref and call the method, it is going to return "actor".