//Bill subclass
public class FixedBill extends Bill
{
  private String fixedBillDesc; //description of expense
  private int fixedBillFrequency; //frequency of bill, monthly, quarterly, etc
  //variables set neutral default values
  public FixedBill()
  {
    fixedBillDesc = null;
    fixedBillFrequency = 0;
  }
  //constructor for FixedBill, sets values for variables
  public FixedBill(String owedTo, String owedFor, double owedAmt, String owedWhen, String owedPaidDate,
                   String owedDesc, int owedFrequency)
  {
    setBiller(owedTo);
    setBillAcct(owedFor);
    setBillAmtDue(owedAmt);
    setBillDueDate(owedWhen);
    setFixedBillDesc(owedDesc);
    setBillPaidDate(owedPaidDate);
    setFixedBillFrequency(owedFrequency);
  }

  //returns fixedBillFrequency text description
  public String fixedBillDecodeFrequency()
  {
    //decides what to return
    switch(fixedBillFrequency)
    {
      case 1 :
        return "monthly";
      case 2 :
        return "quarterly";
      case 3 :
        return "semi-annually";
      case 4 :
        return "annually";
      default :
        return null;
    }
  }

  //sets fixedBillDesc
  public final void setFixedBillDesc(String owedDesc)
  {
    fixedBillDesc = owedDesc;
  }

  //sets fixedBillFrequency
  public final void setFixedBillFrequency(int owedFrequency)
  {
    fixedBillFrequency = owedFrequency;
  }

  //returns fixedBillDesc
  public final String getFixedBillDesc()
  {
    return fixedBillDesc;
  }

  //returns fixedBillFrequency
  public final int getFixedBillFrequency()
  {
    return fixedBillFrequency;
  }

  //returns string output containing all bill information, paid status, and its detailed info
  public String toString()
  {
    String output = String.format(getBiller() + " is owed $" + getBillAmtDue() +" on account " + getBillAcct()+ " by " + getBillDueDate()+"\n");
    if(getBillPaidDate() == null) //checks if bill was paid
    {
      output += "This bill has not yet been paid.";
    } else
    {
     output += "This bill was paid on "+ getBillPaidDate() +".";
    }
    output += "\nThis bill is for " + getFixedBillDesc() + " and is paid " + fixedBillDecodeFrequency() + ".\n";
    return output;

  }

}