Static Data members

  class Account 
  {
    private int accno,balance;
    private static double irate=10.25;
    public void interest(int n)
    {
      double si=balance*irate*n/100;
      System.out.println("Interest is "+si);
    }
    public static void setIRate(double r)
    {
      irate=r;
    }
    public static void showIRate()
    {
      System.out.println("irate is "+irate);
    }
    public Account(int an,int bl)
    {
      accno=an;
      balance=bl;
    }
  }
  class demo
  {
    public static void main(String args[])
    {
      Account.showIRate();
      Account a=new Account(4117,25000);
      Account b=new Account(3012,10000);
      a.interest(5);
      b.interest(2);
      Account.setIRate(9.75);
      Account.showIRate();
      a.interest( 5 ) ;
      b.interest( 2 ) ;
    }
  }

  class Student 
  {
    private int rollno;
    private String name;
    private static int count;
    public void showData()
    {
      System.out.print("RollNo is "+rollno);
      System.out.println("Name is "+name) ;
    }
    public static void showCount()
    {
      System.out.println("Total Studs "+count);
    }
    public Student(int r,String n)
    {
      rollno=r;
      name=n;
      count=count + 1;
    }
  }
  class demo
  {
    public static void main(String args[])
    {
      Student.showCount();
      Student a=new Student(4117,"Amit Jain");
      Student b=new Student(3012,"Seeta Rathi");
      Student.showCount();
      Student c=new Student(5123,"Raja Rao");
      Student.showCount( ) ;
      a.showData();
      b.showData();
      c.showData();
    }
  }

  class MyLib
  {
    public static int sum(int n)
    {
      int s=0;
      for(int i=1;i<=n;i++)
        s=s+i;
      return s;
    }
    public static int factorial(int n)
    {
      int m=1;
      for(int i=1;i<=n;i++)
        m=m*i;
      return m;
    }
  } 
  class demo
  {
    public static void main(String args[])
    {
      int z1=MyLib.sum(10);
      System.out.println("sum is "+z1);
      int z2=MyLib.factorial(5);
      System.out.println("Factorial is "+z2);
    }
  }