. NET Foundation Enhancement 06

Weak references

Set Hashtable dictionary<k,v>

ArrayList list<t>

   classProgram {Static voidMain (string[] args) {            //ArrayList list = new ArrayList ()//{             //New Person () {name= "Kobe", age=35},//New Person () {name= "James", age=30},//New Person () {name= "leaf species", age=25},//}; //list.            Sort (); //for (int i = 0; i < list. Count; i++)//{            //Person p= list[i] as person; //Console.WriteLine (p.name); //}            //Console.readkey ();            int[] Nums = {3,5,2,6,9,1 };  for(inti =0; I < Nums. Length; i++)            {                 for(intj = nums. length-1; J > i; j--)                {                    //if (Nums[j]. CompareTo (Nums[j-1]) <0)//{                    //int n = nums[j]; //Nums[j]=nums[j-1]; //nums[j-1] = n; //}IComparable com=(IComparable) nums[j]; if(Com.compareto (Nums[j-1]) <0)                    {                        intn =Nums[j]; NUMS[J]= Nums[j-1]; Nums[j-1] =N; }                }              }             for(inti =0; I < Nums. Length; i++) {Console.WriteLine (nums[i]);                    } console.readkey (); }    }     Public classperson:icomparable { Public stringName {Get; Set; }         Public stringEmail {Get; Set; }         Public intAge {Get; Set; }         Public intCompareTo (Objectobj) {Person P= obj asPerson ; return  This. Age-P.age; }    } 

Packing and unpacking

Value types go directly to the reference type as boxing; The reference type is converted directly to a value type of unboxing.

 classProgram {Static voidMain (string[] args) {            //int n = 10; //string s = n.tostring ();//not boxing//int m = Int. Parse (s);//It 's not unpacking .//object o = N;//Packing//int x = (int) o;//Unpacking//Console.WriteLine (m); //box unbox appears in the Il language            intn =Ten; Objecto =N; intm = (int) O;            Console.WriteLine (m);        Console.readkey (); }    }

 classProgram {Static voidMain (string[] args) {            //Chinese ch1 = new Chinese (); //Person p = ch1;//Boxing does not occur because it is a reference type//Chinese CH2 = (Chinese) p; //double d = 999.9; //object o = D; //Double D1 = (double) o;//Packing//Console.WriteLine (d1);//unpacking, Output 999.9//Console.readkey (); //int d = 999; //object o = D; //Double D1 = (double) o;//Packing//Console.WriteLine (d1);//An exception occurs when an integer unboxing must be an integral type in boxing//Console.readkey (); //int n = 10; //IComparable com = n;//a boxed interface has occurred that is a reference type//int m = (int) com; //Console.WriteLine (m); //Console.readkey ();            intn =Ten;            Console.WriteLine (n); Objecto = n;//PackingConsole.WriteLine ((int) o);//UnpackingConsole.WriteLine (o);        Console.readkey (); }    }     Public classPerson { Public stringName {Get; Set; }         Public stringEmail {Get; Set; }         Public intAge {Get; Set; }    }     Public classChinese:person {}

    classProgram {Static voidMain (string[] args) {            intn = -;    M1 (n); //call void M1 (double D) does not go boxed            stringS1 ="a"; DoubleD1 =Ten; stringS2 ="b"; intN1 =9; stringFull = s1 + d1 + s2 + n1;//boxed two times, D1 and N1Console.WriteLine (full);        Console.readkey (); }        Private Static voidM1 (Doubled) {Console.WriteLine (d); }        Private Static voidM1 (Objecto) {Console.WriteLine (o); }    }

   classProgram {Static voidMain (string[] args) {            intn =Ten; Objecto = n;//Packing oncen = -; Console.WriteLine (n+","+(int) o);//It took two times to dismantle.Console.readkey (); }    } 

  classProgram {Static voidMain (string[] args) {            //ArrayList arrilist = new ArrayList (); //Stopwatch watch = new Stopwatch (); //Watch.            Start (); //for (int i = 0; i < 1000000; i++)//{            //Arrilist.add (i); //}            //Watch.            Stop (); //Console.WriteLine (watch. Elapsed);//00:00:00.99816//Console.readkey ();List<int> arrilist =Newlist<int>(); Stopwatch Watch=NewStopwatch (); Watch.            Start ();  for(inti =0; I <1000000; i++) {arrilist.add (i); } watch.            Stop (); Console.WriteLine (watch. Elapsed);//00:00:00.014241Console.readkey (); }    } 

var type inference: