InheritanceDemo.java: // StudentName Today's Date public class InheritanceDemo { public static void main(String[] args) { KleenexBox kb1 = new KleenexBox(); KleenexBox kb2 = new KleenexBox(100); Box justABox = new Box(); System.out.println("justABox has area " + BoxArea(justABox)); System.out.println("kb1 has area " + BoxArea(kb1)); System.out.println("kb2 has this many square inches of tissue: " + KleenexArea(kb2)); } public static double BoxArea (Box b) { return b.width * b.length; } public static double KleenexArea (KleenexBox a) { return a.width * a.length * a.numTissues; } } Box.java:
// Student Name Today's Date public class Box { public double width; public double length; public String label; } KleenexBox.java:
// Student's Name Today's Date
public class KleenexBox extends Box { public int numTissues; // A new Kleenex box public KleenexBox() { numTissues = 50; length = 8.0; width = 5.0; } // A new Kleenex box with a specific number of tissues public KleenexBox(int numberOfTissues) { numTissues = numberOfTissues; length = 8.0; width = 5.0; } public String toString() { return ("This box is " + length + " by " + width + " and has " + numTissues + " tissues."); } } Questions: 1. Why can't BoxArea use b.numTissues? (Hint: if you try, Java will give you an error.) 2. Why is the programmer able to pass both justABox and kb1 as arguments to boxArea? (Hint: one word, starts with P.) 3. Why can't the programmer pass justABox as an argument to kleenexArea?

InheritanceDemo.java:

// StudentName Today's Date

public class InheritanceDemo {

public static void main(String[] args) {

KleenexBox kb1 = new KleenexBox();

KleenexBox kb2 = new KleenexBox(100);

Box justABox = new Box();

System.out.println("justABox has area " + BoxArea(justABox));

System.out.println("kb1 has area " + BoxArea(kb1));

System.out.println("kb2 has this many square inches of tissue: " + KleenexArea(kb2));

}

public static double BoxArea (Box b) {

return b.width * b.length;

}

public static double KleenexArea (KleenexBox a) {

return a.width * a.length * a.numTissues;

}

}

Box.java:
// Student Name Today's Date

public class Box {

public double width;

public double length;

public String label;

}

KleenexBox.java:
// Student's Name Today's Date
public class KleenexBox extends Box {

public int numTissues;

// A new Kleenex box

public KleenexBox() {

numTissues = 50;

length = 8.0;

width = 5.0;

}

// A new Kleenex box with a specific number of tissues

public KleenexBox(int numberOfTissues) {

numTissues = numberOfTissues;

length = 8.0;

width = 5.0;

}

public String toString() {

return ("This box is " + length + " by " + width + " and has " + numTissues + " tissues.");

}

}

Questions:

1. Why can't BoxArea use b.numTissues? (Hint: if you try, Java will give you an error.)

2. Why is the programmer able to pass both justABox and kb1 as arguments to boxArea? (Hint: one word, starts with P.)

3. Why can't the programmer pass justABox as an argument to kleenexArea?