Inheritance

  class Account
  {
    protected int accno;
    protected double balance;
    public void open(int an,int bl)
    {
        accno=an;
        balance=bl;
    }
    public void deposit(int amt)
    {
        balance=balance+amt;
    }
    public void withdraw(int amt)
    {
        balance=balance–amt;
    }
    public void showBalance()
    {
        System.out.println("AccNo is " +accno);
        System.out.println("Balance is "+balance);
    }
  }
  class SAccount extends Account
  {
    public void addInterest(double r,int n)
    {
        double si=balance*r*n/100;
        balance=balance+si;
    }
  }
  class demo
  {
    public static void main(String args[])
    {
        Account a=new Account();
        a.open(4117,25000);
        a.deposit(5000);
        a.withdraw(2000);
        a.showBalance();
        SAccount b=new SAccount();
        b.open(3012,10000);
        b.deposit(2000);
        b.showBalance();
        b.addInterest(10.25,3);
        b.showBalance();
    }
  }

  class Set
  {
    protected int n1,n2,n3;
    public void setData(int x,int y,int z)
    {
        n1=x;
        n2=y;
        n3=z;
    }
    public int sum()
    {
        int s=n1+n2+n3;
        return s;
    }
  }
  class XSet extends Set
  { 
    public double mean()
    {
        double m=sum()/3.0;
        return m;
    }
  } 
  class demo
  {
    public static void main(String args[])
    {
        Set a=new Set();
        a.setData(4,6,7);
        System.out.println("Sum of set a is "+a.sum());
        XSet b=new XSet();
        b.setData(10,20,25);
        System.out.println("Sum of set b is "+b.sum());
        System.out.println("Mean of set b is "+b.mean());
    }
  }

  class Rect
  {
    protected int L,B;
    public void setDimension(int m,int n)
    {
        L=m;
        B=n;
    }
    public void area()
    {
        int a=L*B;
        System.out.println("Area is "+a); 
    }
  }
  class Xrect extends Rect
  {
    public void perimeter()
    {
        int p=2*(L+B);
        System.out.println("Perimeter is "+p);
    }
  }
  class demo
  {
    public static void main(String args[])
    {
        Rect a=new Rect();
        a.setDimension(5,7);
        a.area();
        Xrect b=new Xrect();
        b.setDimension(10,20);
        b.area();
        b.perimeter();
    }
  }