Boxing and Unboxing

Question

hi what is boxing and why it is used

Kirtan Patel · Answer

Friend, Here is Explanation. Boxing is the process of converting a value type to the type object or to any interface type implemented by this value type. When the CLR boxes a value type, it wraps the value inside a System.Object and stores it on the managed heap. Unboxing extracts the value type from the object. In the following example, the integer variable i is boxed and assigned to object o . int i = 123; object o = (object)i; // boxing o = 123; i = ( int )o; // unboxing

theLizard · Answer

Kirtan, amazing, is it possible for you to come up with your own answers? I have seen you do this to a number of people who gave the right answer to a question. What poses-es you to take some one elses answer change it and claim it to be yours?

Purushottam Rathore · Answer

Boxing: The process of converting from a value type to a reference type is called boxing. Boxing is an implicit conversion. Boxing example: using System; class ConversionSamp { static void Main() { int a = 5; Object obj = a; Console.WriteLine(a.ToString()); Console.WriteLine(obj.ToString()); } } Unboxing: The process of converting from a reference type to a value type is called unboxing. Unboxing example: using System; class ConversionSamp { static void Main() { Object obj = 5; int a = (int)obj; Console.WriteLine(a.ToString()); Console.WriteLine(obj.ToString()); } }

Lalit M · Answer

Boxing is what happens when a value-type object is assigned to a reference-type variable. Unboxing is what happens when a reference-type variable is assigned to a value-type variable. Value-type variables include the numeric types, System.Char, System.Boolean, System.DataTime, enumerations and structures. Reference-type variables include all arrays and classes. In the following C# example, the variable PI is a double and this is allocated on the stack. However, when it is passed to the function foo, it must be "boxed" which involves making a copy of it on the heap. There is overhead in this. Within foo, even though o references the value 3.14159, it must be cast back (unboxed) to a double to be used. Again, there is overhead in this. static void foo(object o) { double x = (double) o; // unboxing Console.WriteLine( x ); } static void main() { double PI = 3.14159; foo( PI ); // PI is boxed when passed to o } Boxing and Unboxing with examples more example --------------- Boxing is converting a value type to reference type Unboxing is an explicit operation. Eg. In C# : int X 1; Object Y; int Z; Y X; -------------> This is BOXING Z (int)Y; ----------------> This is UNBOXING

Boxing and Unboxing

Answers (4)