week 4

struct value type instantiated without new ctor must have para cant use default ctor class reference type struct implicitly sealed cant be inherited can be initiated only if field is const or static interface contain only function name no implementation. can override & member hiding abstruct class has limits interface often starts with capital I implementation written in class which use it abstruct class often is base class interface can be used in anywhere public void IStorable { void Read(); int Status {get;set;} } if you inherit it,you must implement it class can have more than one interface Public Class D:ISoreable,IDocumentable when we use it we should look up which methods must be implemented the interfaces being inherited by interface must also be implemented foreach(D d in folder) IStorable isD = d as IStorable left operand as right operand if interface hasnt be implemented isD=null multi inheritance forbidden multi interface allowed override interface polymorphism public void D{ public virtual void read(){} } public class Note:D{ public override void read(){} public void new store(){} } type safe classes Dictionary Array implementing IEnmunerable ICollection declare array type[]name automatically assigned to null foreach (Employee e in emp Array) { Console.Writeline(e.ToString()); } E []e={new E(1),new E(2)}; D(params int[]i) t.D(5,6,7,8); t.D(array); type[,]array=new[rows,cols]; type[,,]array=new[x,y,z]; c# should obey rows and columns jagged Array.Length get the number of rows jagged Array[x].Length get the number of x row yield return the next time it starts at where it was in the last time Dictionary if it cant find the word it may throw exception System.Text.StringBuilder builder add on the base StringLiteralOne"\\\\My" StringVerbatismLiteralOne@"\\My" StringLiteralOne"\n" StringVerbatismLiteralOne" "(true backspace) StringVerbatismLiteralOne@""v"" "v"