// Bank accounts in Kotlin: basic classes and inheritance

// open class means class can be inherited by another class
open class account(n:String, initial:Double)  // don't put val, var here as
{    	   		     		      // that makes them public
   public val name = n;    // val can't be changed 
   protected var balance = initial;   // var can

   public open fun inquiry():Double  // default public (not same as c#,java)
   { return balance; }

   open fun withdraw(amt:Double)  // if not open, can't override (final)
   { if (amt<balance && amt>0) balance -= amt; }

   open fun deposit(amt:Double)
   { if (amt>0) balance += amt; }
}//open class account


// subclasses
open class savings(n:String, ib:Double) : account(n,ib)
{
   var gift = "toaster"
     private set;  // gift can only be changed internally
   override fun deposit(amt:Double)
   { if (amt>=10000) println("Congratulations "+name+", you won a "+gift);
     super.deposit(amt); // hmmm - no error of 10000 instead of 10000.0 here
   }
}//savings


/* This Bank lets you select your minimum balance threshold: whenever
your balances dips below the minimum min, you will be charged a fee of
$5000/min.  So if your chosen min is $1000, then your will be charged
$5 when a withdraw dips your balance below $1000.  However, if your
min is $5000, then you will be charged $1 if your balance goes below
$5000.  */

open class checking(n:String, ib:Double, val min:Double) : account(n,ib)
{
  private fun chargefee() { balance -= 5000/min;}
  override fun withdraw(amt:Double)
  {
     super.withdraw(amt)
     if (balance<min) chargefee()
  }
}

/*
Brothers F. Arman Imal and P. Artyan Imal both attend Hofstra and major in
computer science.  While "Artyan" is outgoing and talkative, "Arman" is
rather reserved and quiet.  Their different life styles lead to different
spending and saving habits...
*/

fun main(argv:Array<String>)
{
   // create accounts for the Imal brothers:
   val acct1:account = savings("F. Arman Imal",1000.0);          
   val acct2 = checking("P. Artyan Imal",1500.0,1000.0);  // type inferred

   acct1.withdraw(400.0)  // Arman needs more feed
   acct2.deposit(300.0)   // Artyan got a check from mom for textbooks
   acct1.deposit(10000.0) // Arman deposits hard earned savings
   acct2.withdraw(1000.0) // Artyan buys more party supplies
   println("balance for "+acct1.name+": "+acct1.inquiry())
   println("balance for "+acct2.name+": "+acct2.inquiry())
}//main