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"