difference between ref and out parameters

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difference between ref and out parameters

Author:shailendra Chauhan

Ref and Out parameters is used to pass an argument within a method. In this article, you'll learn the differences between these.

Ref

The REF keyword is used-to-pass an argument as a reference. This means if value of that parameter was changed in the method, it gets reflected in the calling method. An argument, that's passed using a ref keyword must be initialized in the calling method before it's passed to the called Method.

Out

The Out keyword are also used to pass a argument like ref keyword, but the argument can being passed without assigning any VA Lue to it. An argument, which is passed using a out keyword must being initialized in the called method before it returns back to calling Method.

Program with ref and out keyword

         Public Static voidMain ()//Calling Method        {            intVal1 =0;//must be initialized            intVal2;//OptionalExample1 (refval1); Console.WriteLine (VAL1); //val1=1Example2 ( outval2); Console.WriteLine (VAL2); //val2=2        }        Static voidExample1 (ref intValue//called method{Value=1; }        Static voidExample2 ( out intValue//called method{Value=2;//must be initialized        }    /*Output 1 2

Note

1. Do is confused with the concept of passing by reference and the concept of reference type. These concepts is not the same.
2. A value type or a reference type can be passed to method parameter by using ref keyword. There was no boxing of a value type when it was passed by reference.
3. Properties cannot is passed to ref or out parameters since internally they is functions and not members/variables.

Ref and out in method overloading

Both ref and out cannot is used in method overloading simultaneously. However, ref and out is treated differently at Run-time but they is treated same at compile time (CLR doesn ' t differenti Ates between the IT created IL for ref and out). Hence methods cannot is overloaded when the one method takes a ref parameter and other method takes an out parameter. The following methods is identical in terms of compilation.

        Public voidMethod ( out intA//Compiler Error "cannot define overloaded"        {            //method that differ only on ref and out "A =0;//must be initialized        }         Public voidMethod (ref inta) {//method that differ only on ref and out "}

However, method overloading can be do, if one method takes a ref or out argument and the other method takes simple AR Gument. The following example is perfectly valid to be overloaded.

class MyClass        {            publicvoid Method (int  a)            {            }            public  void method (outint  a)            {                //  method differ in Signature.                0 // must be initialized             }        }

What does you think?

I hope you'll enjoy the ref and out keywords while programming with C #. I would like to has feedback from my blog readers. Your valuable feedback, question, or comments about this article is always welcome.

difference between ref and out parameters