1. Clicker questions 10/3/13
CSE 1102 Fall 2013

2. public class <PartClass> {…
private <ContainerClass> _<container>;
public <PartClass(<ContainerClass> <aContainer>) {
_<container> = <aContainer>; }
public class HatPart { …
private Hat _myHat;
public HatPart(Hat aHat){
_myHat= aHat; }
In the above code, what is the purpose of the parameter aHat?
It sets a default value for _myHat object
It is used to initialize _myHat when we instantiate a HatPart
It is used to instantiate _myHat when we instantiate a HatPart
It lets us change the value of _myHat in an existing HatPart instance
All of the above
In the above code, what is the purpose of the parameter <aContainer>?
It sets a default value for _<container> object
It is used to initialize _<container> when we instantiate a <PartClass>
It is used to instantiate _<container> when we instantiate a <PartClass>
It lets us change the value of _container in an existing <PartClass> instance
All of the above

3. Notice from the diagram that Rectangle is not linked to Draggable
Notice from the diagram that Rectangle is not linked to Draggable. What does this imply?
HatPart must define all of the Draggable methods independent of Rectangle
Someone forgot to put the link in the diagram
Rectangle.java does not include the phrase implements Draggable
Either A or B above
Either B or C above

4. …
OilTanker oily = new Truck(200);
oily.move();
In the code above, which move method gets executed?
The move method defined in OilTanker
The move method defined in Truck
The move method defined in Vehicle
All of the above
The code does not work

5. private Tree _tree;
...
_tree = new Oak();
_tree.prepareForWinter();
Given the above class diagram, and the code on the right, what happens when the last line (_tree.prepareForWinter();) is executed?
The prepareForWinter method defined in Oak is used
The prepareForWinter method defined in Pine is used
The prepareForWinter method defined in Tree is used
The last line does not get executed since _tree = new Oak(); causes an error
None of the above

6. public class Crow extends Bird {
private Tree _myTree;
...
public void battenDown(){
_myTree.??? }
Suppose Russell is a Crow, and lives in an Oak. What can replace ??? above?
prepareForWinter();
absorbWater();
dropLeaves();
Any public method from Tree or anything above it in the inheritance hierarchy
Any public method from Oak or anything above it in the inheritance hierarchy

7. public class Oak extends Tree {
...
public void prepareForWinter(){
this.dropLeaves();
??? }
Suppose an Oak prepares for winter like a Tree, but it drops its leaves first. What code should replace ??? above?
Tree.prepareForWinter();
super.this();
super.prepareForWinter();
this.absorbWater();
super(this);

8. Example: Death Race 2000
Your task: to produce a new video game. It works by instantiating a DeathRace between 2 cars using the constructor, then calling its runTheRace method, which returns the winner.
public class DeathRace {
Car _car1, _car2;
public DeathRace(Car c1,Car c2){
_car1 = c1;
_car2 = c2;
... }
public Car runTheRace(){
Car winner;
_car1.move();
_car2.move();
return winner;

9. Car

10. public interface Holder {
void add(Holdable h);
Holdable release(); }
public interface Holdable {
Weight getWeight);
Dimension getDimensions(); }
The formal parameter type for add in Holder is Holdable. What does that require in any non-abstract class that implements Holder?
It has a method add whose formal parameter type implements Holdable
The definition of its add method has signature add(Holdable)
It will not compile, since Holdable is an interface, not a class.
It has an abstract add method
None of the above