C# week5_2

23/02/2010

<static, non-static>

 
 

class student

{

public int i;

static public int j=5;

}

student s1 = new student();

student s2 = new student();

 
 

j=5: global

i=0

i=0

s1 s2

 
 

Static: initialize static value of your class

*static can't have any parameter.

 
 

class student

{

int id; ←object valuables or instance valuables

int age;

static string cname; ←class valuables

 
 

student(int i,j)

{

id=i;

age=j;

}

}

 
 

static student() ←can't have any parameter (error)

{

cname="GDIT";

}

*static object runs first ready. (Share = global)

 
 

1. Compiler helps
   

   class xyz
   

   {
   

   static void Main() ←private (default private)
   

   {
   

   Console.WriteLine("Hello");
   

   }
   

   }
   

   class ABC
   

   {
   

   static void Main()
   

   {
   

   xyz x=new xyz(); ←It will work, because even though xyz is public, it helps coming from compiler.
   

   }
   

   }
   

    
    

2. Compiler doesn't help
   

   class xyz
   

   {
   

   static void Main() ←private (default private)
   

   {
   

   Console.WriteLine("Hello");
   

   }
   

   xyz();
   

   }
   

   class ABC
   

   {
   

   static void Main()
   

   {
   

   xyz x=new xyz(); ←It will be error, because it has already initialized in the class, so it's public. (Compiler doesn't support)
   

   }
   

   }
   

    
    

    
    

   class ABC
   

   {
   

   public static void xyz()
   

   *it is required if this method is called outside this class.
   

   {
   

   Console.WriteLine("Hello");
   

   }
   

   }
   

   class one
   

   {
   

   static void Main()
   

   {
   

   ABC.xyz();
   

   }
   

   }
   

    
    

3. Class program sample
   

   class Program
   

   {
   

   static void Main(string[] args)
   

   {
   

   student s = new student(1, 20, "xyz");
   

   student s1 = new student(2, 22, "abc");
   

   student s2 = new student(3, 23, "def");
   

   student s3 = new student(4, 24, "mno");
   

    
    

   Console.WriteLine("The student id is " + s.sid);
   

   Console.WriteLine("The student age is " + s.age);
   

   Console.WriteLine("The student name is " + s.name);
   

   Console.WriteLine("The student coursename is " + student.coursename);
   

    
    

   Console.WriteLine("The student id is " + s1.sid);
   

   Console.WriteLine("The student age is " + s1.age);
   

   Console.WriteLine("The student name is " + s1.name);
   

   Console.WriteLine("The student coursename is " + student.coursename);
   

    
    

   Console.WriteLine("The student id is " + s2.sid);
   

   Console.WriteLine("The student age is " + s2.age);
   

   Console.WriteLine("The student name is " + s2.name);
   

   Console.WriteLine("The student coursename is " + student.coursename);
   

    
    

   Console.WriteLine("The student id is " + s3.sid);
   

   Console.WriteLine("The student age is " + s3.age);
   

   Console.WriteLine("The student name is " + s3.name);
   

   Console.WriteLine("The student coursename is " + student.coursename);
   

    
    

   }
   

   }
   

   class student
   

   {
   

   public int sid;
   

   public int age;
   

   public string name;
   

   public static string coursename;
   

    
    

   public student(int i, int j, string s)
   

   {
   

   sid = i;
   

   age = j;
   

   name = s;
   

   }
   

    
    

   static student() //constructor don't need public. (It has already initialized, so we can call this class from outside.)
   

   {
   

   coursename = "GDIT";
   

   }
   

   }