Boxing and Unboxing

 23th Day

Hey Guys, I hope that you are Enjoying with my blogs writing and in previous blog we have  learnt about Memory Leak , Garbage Collector and Today's we will learn Boxing and Unboxing . Let's see

Boxing ,When a value type is move to a reference type its called Boxing and vice versa for Unboxing. 

For Example In this code

int i = 10;//Value type

object o = i;//Boxing

int y=(int)o;//Unboxing

• Boxing is an implicit Conversion from value type to reference type.
• Here i=10 has stored in stack with address above shown in diagram its moving value i to o its a value type.

      Unboxing

• Unboxing is an explicit Conversion from reference type to value type.
• And in heap o=10 its also moving from o to y its a reference type.

       Let's see the result of boxing and Unboxing

        static void Main(string[] args)

        { //Line1 Warm period

Heavyloop();

Heavyloop();

//Line2

            Stopwatch s1 = new Stopwatch();

            s1.Start();

            Heavyloop();

            s1.Stop();

            //Line3

            Console.WriteLine(s1.ElapsedTicks);

            Console.WriteLine("Hello World!");

            Console.ReadLine();

        }

• Line 1: Function will run as it is for warmup period and then actual measuring will start from Line 2.  
• Line2: Stopwatch measure time below of milli sec and now will start measure its ElapsedTicks.
        static void Heavyloop()

          {

              for(int i=0; i<100000;i++)

              {

                  int z = 10;//Value Type

                  object x = z;// reference type

              }

          }

• static void Heavyloop(), in this function we written code for boxing and Unboxing how much time it will take in performance. For that we set stopwatch.
• stopwatch, find function how much time taking for execution. 
• Now let's run this code ,sometimes give 5 digits figure or 4 digits figure
• 1st  output ElapsedTicks: 
                                 
• 2nd  output ElapsedTicks 
  
   
• 3rd  output ElapsedTicks

                                              

     

• It means that in non Primitive Data type, Due to Boxing and Unboxing its figure digits are different most of the time may be 4 to 5 digits.
• But in case of Primitive Data type always be the same figure due to no Boxing , Unboxing occurs.

      Collection 

• It is similar to array, it provides more flexible way to work with group of objects.
• It can grow and shrink Dynamically. 
              // line 1

             int[] salesfigures = new int[] { 1000, 2000 };

             // line 2

              ArrayList l = new ArrayList();

              l.Add(1);

              l.Add("one");

              Console.WriteLine("Hiii"); /line 3

              List<int> Is = new List<int>();

              Is.Add(1);

  
  
• Line 1: It is Strongly typed and there are no Boxing/Unboxing so its performance will be faster. Its resizing is difficult. This is an Array.

• Line 2: Boxing/Unboxing will be happen that's why its performance will be slower but it will be very flexible. This is the array list.

Suppose we want flexible as well as good performance for that we have to create Generic collection i.e. "A collection which has strongly typed ,flexibility as well as  it improves the performance, Avoiding Boxing/Unboxing is called Generic Collection ".

• List<T>, Dictionary< Tkey, Tvalue>, sortedlist<Tkey,Tvalue>, Queue<T>, Stack<T>, Hashset<T> are used in Generic Collection.
• There are three types of Collection

1. Array
2. Array list
3. Generic list.

                        Must watch this video for more detail learning...

                                  

                              Thank You...! for reading my Article...