In this lecture we will continue with buttons and work with the Vendomatic Button for individual project 1. We will also work some more on the Fraction class:

public class Fraction {
    private int myNumerator;
    private int myDenominator;
    private boolean myIsValid;

    //constructor
    public Fraction (int num, int den) {
        myNumerator = num;
        myDenominator = den;
        if (den==0)
           myIsValid = false;
        else
           myIsValid = true;
    }

    // accessor methods
    public int GetNumerator() {
        return myNumerator;
    }

    public int GetDenominator() {
        return myDenominator;
    }

    public double GetDecimalEquivalent() {
        if (myIsValid)
            return ((double)myNumerator)/myDenominator;
        else
            return Math.NaN;      // Not a number.
    }

    public boolean IsValid() {
        return myIsValid;
    }

    //modifier methods
    public void AddFraction(Fraction f) {
        if (f.IsValid() && IsValid()) {
          int n = myNumerator*f.GetDenominator() +
                  myDenominator*f.GetNumerator();
          int d = myDenominator*f.GetDenominator();
          myNumerator = n;
          myDenominator = d;
        } else
          myIsValid = false;
    }

    public void DivideFraction(Fraction f) {
                                    // Your code goes here
    }

    public void MultiplyFraction(Fraction f) {
                                    // Your code goes here
    }

    public void SubtractFaction(Fraction f) {
                                   // Your code goes here
    }

    // other methods
    public void PrintFraction() {
        if (myIsValid)
           System.out.println(myNumerator + "/" + myDenominator);
        else
           System.out.println("Not a Number (NaN)");
    }
}

public class FractionMain {

    /**
     * Constructor.
     */  
    public FractionMain () {
    }

    public static void main(String args[]) {
        Fraction f1 = new Fraction(3, 4);
        f1.PrintFraction();
        System.out.println("Numerator is " + f1.GetNumerator());
        System.out.println("Denominator is " + f1.GetDenominator());
        double t = f1.GetDecimalEquivalent();
        System.out.println("Decimal is " + t);
        Fraction f2 = new Fraction(15,17);
        f1.AddFraction(f2);
        f1.PrintFraction();
        f2.PrintFraction();
                                  // put some more tests here
    }
}