What is the difference between ref and out keywords?

Question

Rajeesh Menoth · Answer

Hi, Ref : If you want to pass a variable as ref parameter you need to initialize it before you pass it as ref parameter to method Out : Out parameter values must be initialized in called method before it return values to calling method Reference : http://www.aspdotnet-suresh.com/2014/06/csharp-difference-between-ref-and-out-parameters-example.html

Thennarasu N · Answer

The ref modifier means that: The value is already set and The method can read and modify it. The out modifier means that: The Value isn't set and can't be read by the method until it is set. The method must set it before returning.

Bulbul Ahmed · Answer

Ref is used for pass an argument as a reference, means if the value of that parameter changed it reflects in the calling method. Out Keyword is used to pass an argument but must be initialized in called method and it returns back to calling method. Ref tells the compiler that object is initialized before entering the function but Out tells compiler object will be initialized inside the function.

Kanniyappan Krish · Answer

Hi, Please go through below article http://www.aspdotnet-suresh.com/2014/06/csharp-difference-between-ref-and-out-parameters-example.html

Ananth G · Answer

Ref Keyword The ref keyword passes arguments by reference. It means any changes made to this argument in the method will be reflected in that variable when control returns to the calling method. Example code public static string GetNextName( ref int id) { string returnText= "Next-" +id.ToString(); id+=1; return returnText; } static void Main( string []args) { int i=1; Console.WriteLine( "Previousvalueofintegeri:" +i.ToString()); string test=GetNextName( ref i); Console.WriteLine( "Currentvalueofintegeri:" +i.ToString()); } Out Keyword The out keyword passes arguments by reference. This is very similar to the ref keyword. Example Code public static string GetNextNameByOut( out int id) { id=1; string returnText= "Next-" +id.ToString(); return returnText; } static void Main( string []args) { int i=0; Console.WriteLine( "Previousvalueofintegeri:" +i.ToString()); string test=GetNextNameByOut( out i); Console.WriteLine( "Currentvalueofintegeri:" +i.ToString()); }

Bikesh Srivastava · Answer

I have already written article on this topic with practicle explanation . click here. https://bikeshsrivastava.blogspot.in/2016/06/part-22what-is-ref-and-out-in-c.html

Sandip G. Patil · Answer

Main and important difference is the only difference is that a variable you pass as an out parameter doesn’t need to be initialized but passing it as a ref parameter it has to be set to something or need to be initialize.

Bulbul Ahmed · Answer

For better understand of Ref and Out , please visit the following link. It might help you. http://www.codeproject.com/Articles/550479/Ref-and-Out-The-Inside-Story

Chinmaya Dash · Answer

So it means both the case if we will assign the value to those parameter it will react. can you give some real time example on this Thanks in advance

What is the difference between ref and out keywords?

Answers (9)