bankloan.fool

let

  class Account (money:int) {
    fun getMon:int () money;
  }
  
  class TradingAcc extends Account (invested:int) {
    fun getInv:int () invested;
  }
  
  class BankLoan (loan: Account) {
    fun getLoan:Account () loan;
    fun openLoan:Account (m:TradingAcc) if ((m.getMon()+m.getInv())>=30000) 
      then {new Account(loan.getMon())} 
      else {null};
  } 
  
  class MyBankLoan extends BankLoan (loan: TradingAcc) {
    fun openLoan:TradingAcc (l:Account) if (l.getMon()>=20000) 
      then {new TradingAcc(loan.getMon(),loan.getInv())} 
      else {null};
  } 
    
  var bl:BankLoan = new MyBankLoan(new TradingAcc(50000,40000));
  var myTradingAcc:TradingAcc = new TradingAcc(20000,5000);
  var myLoan:Account = bl.openLoan(myTradingAcc);
      
in print(if (myLoan==null) then {0} else {myLoan.getMon()});