diff --git a/cs623/proj1/Makefile b/cs623/proj1/Makefile
index 74533ea..1ce1411 100644
--- a/cs623/proj1/Makefile
+++ b/cs623/proj1/Makefile
@@ -2,7 +2,7 @@
 MAINCLASS := RetirementCalculator
 
 all:
-	javac $(MAINCLASS).java
+	javac *.java
 
 .PHONY: run
 run:
diff --git a/cs623/proj1/RetirementCalculator.java b/cs623/proj1/RetirementCalculator.java
index 02a8cfe..2bea63b 100644
--- a/cs623/proj1/RetirementCalculator.java
+++ b/cs623/proj1/RetirementCalculator.java
@@ -13,6 +13,29 @@ class RetirementCalculatorPanel extends JPanel implements ActionListener
 {
     private RetirementCalculatorModel myModel;
 
+    private HashMap<String, Field> myFields;
+
+    public class Field extends JTextField
+    {
+        private String myName;
+
+        public Field(String name, String dflt)
+        {
+            super(dflt);
+            myName = name;
+        }
+
+        public String getName() { return myName; }
+    }
+
+    public void addField(JPanel addto, String caption, String name, String dflt)
+    {
+        addto.add(new JLabel(caption));
+        Field field = new Field(name, dflt);
+        myFields.put(name, field);
+        addto.add(field);
+    }
+
     public RetirementCalculatorPanel()
     {
         JPanel inner = new JPanel(new GridLayout(3, 2));
diff --git a/cs623/proj1/RetirementCalculatorModel.java b/cs623/proj1/RetirementCalculatorModel.java
index 66e2336..44cbd93 100644
--- a/cs623/proj1/RetirementCalculatorModel.java
+++ b/cs623/proj1/RetirementCalculatorModel.java
@@ -4,37 +4,42 @@ import java.util.*;
 public class RetirementCalculatorModel
 {
     /* input fields */
-    private double myCurrentIncome;
-    private double myIncomeWanted;
-    private double myEmployerPension;
-    private double myPartTimeIncome;
-    private double myOtherIncome;
-    private double myAge;
-    private double myRetirementAge;
-    private double mySavings;
-
-    /* calculated fields */
-    private double mySocialSecurity;
-    private double myRetirementIncome;
+    private HashMap<String, Double> myFields;
 
     public RetirementCalculatorModel()
     {
         reset();
     }
 
+    public void setField(String name, double value)
+    {
+        myFields.put(name, value);
+    }
+
+    public double getField(String name)
+    {
+        return (myFields.containsKey(name)) ? myFields.get(name) : 0;
+    }
+
     public void reset()
     {
-        myIncomeWanted = 0;
-        myEmployerPension = 0;
-        myPartTimeIncome = 0;
-        myOtherIncome = 0;
-        myAge = 30;
-        myRetirementAge = 65;
+        myFields.clear();
+
+        setField("current income", 0);
+        setField("income wanted", 0);
+        setField("employer pension", 0);
+        setField("part time income", 0);
+        setField("other income", 0);
+        setField("age", 30);
+        setField("retirement age", 65);
+        setField("savings", 0);
+
+        calculate();
     }
 
     public void calculate()
     {
-        mySocialSecurity = calculateSocialSecurity();
+        setField("social security", calculateSocialSecurity());
     }
 
     private double calculateRetirementFactor()
@@ -44,9 +49,10 @@ public class RetirementCalculatorModel
     
     private double calculateSocialSecurity()
     {
-        if      (myCurrentIncome < 25000.0)
+        double current_income = getField("current income");
+        if      (current_income < 25000.0)
             return 8000.0;
-        else if (myCurrentIncome <= 40000.0)
+        else if (current_income <= 40000.0)
             return 12000.0;
         else
             return 14500.0;