basic: //利用out, 不用給i,j assign初始值 int i,j; f(out i, out j) {} //using, 括號外自動destroy對象 using (font thefont == new font("ariel", 10.0f)){} //constants const int i = 32; //enumeration enum e {a=5,b=8} int i = (int) e.a; //turn buff data to string encoding.ascii.getstring(buff, 0, bytesread) // read data string s = console.readline() int j= convert.toint32(s); //get textbox value and convert to double double left = double.parse(textbox1.text); application.doevent(); //this will let app deal with event array: a[] a = new a[5]; // a[0]to a[5] is null int[] arr = new int[2] {1,2} int[] arr = {2,3,4,5} foreach(a a in arr_a) {} for(int i=0; i<arr.length; i++) {} //rectangular arrays int[,] rectarray = new int[4,5] int[,] arr = {{1,2,3,4},{1,2,3,4}{1,2,3,4}}; //init //jagged array, 數組中包含數組，各維不等長 // ja[0].length is length of ja[0] int [][] ja = new int[4][]; //using params transfer a array to a function //using f(1,2,3,4) to call the function f(params int[] values){ foreach (int[] a in values) {} } collection interface: indexers: //define a indexers public myclass this[int offset] {get{};set{}} //call it employee joe = bostonoffice["joe"]; ienumerable: //return a ienumerator object getenumerator() ienumerator: reset(){} current(){} movenext(){} icomparable: //class inherit icomparable interface //implement compareto() method compareto() arraylists: count get number of elements add() add an object clear() remove all objects reverse() reverse order of elements sort() sort the elements function: //default by value f(int x){} //by reference f(ref int x){} class: //存取： public, private, protected, internal, protected internal this, static //static member must be init in class //繼承 class a: b {} //多態 virtual，override //init對象 employee emp1 = new employee();
//先隱式轉換3為roman roman r4 = r1 + 3; //先顯式轉換7.5為roman roman r5 = r1 +(roman)7.5;
// 運算符重載,先返回int, 然后用隱式轉換 public static roman operator+ (roman l, roman r) { return (l.val+r.val); } //顯式轉換 public static explicit operator roman(float val) { return new roman(val); } //隱式轉換 public static implicit operator roman(int val) { return new roman(val); } //properties, 注意大小寫 public int age { get {return age;} set {age = value;} }
//interface //interface methods must be implement in class public interface ia {} //is 測試類是否從接口繼承 if (a is ia) {ia c = (ia) a; } //as 測試類是否從接口繼承 ia c = a as ia; if (c != null) {} //interface properties pubiic interface iaa: ia { float f{get;set;} } //mutiface interface inheritance public class c: ia,
