import awb.*;
import java.awt.*;
import java.awt.event.*;

public class CompInterest extends java.applet.Applet implements ActionListener
{
    TextField mInstruct, mBalance;
    DoubleField gRate, gPrinc, gPay;
    Button bCompute;
    IntField gMonths;
    double rate, princ, pay, balance;
    int months, k;
    
    public void init()
    {   
        mInstruct = new TextField(80);
        mInstruct.setText
           ("Enter principal, rate, payment, #months; then press 'Compute'");
        gPrinc = new DoubleField(10);
        gRate = new DoubleField(10);
        gPay = new DoubleField(10);
        gMonths = new IntField(10);
        bCompute = new Button("Compute");
        mBalance = new TextField(80);
	bCompute.addActionListener(this);
        add(mInstruct);
        add(gPrinc);
        add(gRate);
        add(gPay);
        add(gMonths);
        add(bCompute);
        add(mBalance);
    }
        
    public void actionPerformed(ActionEvent event)
    {
	Object cause = event.getSource();

        if (cause == bCompute)                                                    
        {
            princ = gPrinc.getDouble();
            rate = gRate.getDouble()/12;
            pay = gPay.getDouble();
            months = gMonths.getInt();
            balance = princ;
            k = 0;
            while (k < months)
            {
                balance = balance*(1.0 + rate) - pay;
                k = k + 1;
            }
            mBalance.setText("After " + months + " months at " + 100*rate*12 + 
                 "% and payments of " + pay + " the balance is " + balance);
        }
    }
}