DP Computer Science Questionbank

Define the term mutator method.

State one additional instance variable of type boolean which could be added to the class Race as indicated above.

Many swimmers in the event have names that cannot be represented using basic character sets such as ASCII.

Describe one feature of modern programming languages that allows the wide range of students’ names to be represented correctly.

Construct the code fragment for the given situation that will copy swimmers and times into two parallel arrays named tempSwimmer and tempTime.

Construct code for the constructor of the class Swimmer that instantiates an object with parameters name and school. The event IDs should be set to “empty” and the times to 0.0

Sketch the resulting swimmer array in finals.

Construct the code fragment that will copy the names of the 8 fastest swimmers in ascending order of time from the array tempSwimmer to the array swimmers in the race finals.

State the implication of the use of the term static in the Payment class.

Outline an alternative method of initializing these variables that would not require the use of the code in the constructor.

The Payment class method addFoodItem() is passed a FoodItem object as a parameter.

Construct the method addFoodItem().

With reference to two examples from the classes in the resource, explain the benefits gained by the use of different data types.

Describe the purpose of the following statement:

private FoodItem[] fi = new FoodItem[100]

Construct statements, in code, that will print out the following: The number of drink items ordered by table 40.

State the output after this code is executed.

Construct statements, in code, that will print out the following: The item code of the third food item ordered by table 2.

Construct the method findPrice(). You may assume that the item exists in the array.

When a customer wishes to pay the bill, the $\mathrm{calculateBill} ( )$ method is called. If the bill was for table 10 then the following call would be made:

double finalBill = tables[10].calculateBill(Item[] pl);

Construct the calculateBill() method. You should make use of any previously defined methods.

Construct the method search implementing a linear search. Use the first compareWith() method in the Arrival object.

You may assume that an Arrival object with the given flightID exists in the array inbound.

Construct a method showDelayed() that outputs the IDs of all delayed flights in the array inbound that have not yet landed and that have an ETA before a given time t. The time t is passed as a String parameter.

When a flight is delayed, a method in FlightManagement is used to find and update the flight with the delay and to reorganize the array so that it remains sorted for the ETA.

Describe how this method would be implemented using the methods provided.

Define the term method signature.

Without using a sorting algorithm, construct the method add(Arrival newArrival) that inserts a newArrival in the sorted array inbound. You may assume that newArrival has been instantiated and that the array inbound is not full.

Define the term identifier.

State the code fragment that instantiates an array line of 20 Cart objects.

Construct the method public void joinLine(Cart newCart) that adds a newCart to line in the next empty array location. You may assume that line is not full.

Construct the code for a method split (part of the class POSsystem), that takes an existing, non-empty POSline as a parameter. It should copy every second cart from the original line into a new line. Afterwards it should delete every second cart from the original line.

An example call in POSsystem would be: POSline number2 = split(number1), where number1 is an existing POSline.

You may use any method declared or developed.

Construct the method public Cart leaveLine(int n) that removes the cart at position n from line by shifting down all the array entries bigger than n, before returning the indicated Cart object. You may assume that a cart exists at position n.

As a result of the simulation, the company has decided to create a new POS system for their supermarkets.

There have been discussions about adapting existing open source code when developing modules of the new POS system.

Describe two ethical issues that may arise if modules of the new POS system are developed from open source code.

Outline one effect of using the modifier static when declaring a variable.

Construct code to create an instance of the Vehicle class that has a registration of X1234567.

Outline why it is necessary to use the keyword this in the setBroken method of the Vehicle class.

Construct code that sets the colour of the object created in part (i) as black.

Construct the method pay in the Vehicle class that returns the admin fee stored in the variable AdminFee if the vehicle has stayed for five hours or less; otherwise, it returns 0.

Construct the method pay in the Car class, where it uses the vehicle method pay but adds the charge for the amount of time spent in the parking area.

The array vehicles[] in the ParkingArea class is used to store instances of the Car or Motorbike class.

Outline why Vehicle is a valid type for this array.

Describe, without writing code, any changes required to the addVehicle method and the ParkingArea class to make the new voucher scheme work.

Identify three other tests you might perform on the completed code to prove that it functions correctly.

The removeVehicle method of the ParkingArea class searches in the array for a Vehicle object with a specified registration plate, then removes it by setting that array index to null.

The method returns a reference to the Vehicle object that has been removed from the array, or null if no matching registration plate was found.

Construct the removeVehicle method.

With the use of two examples other than private, outline how the choice of this modifier affects the way in which these variables are accessed or used.

State the output given by the following statement:

System.out.println(allPoints[2].getMemberId());

State the output given by the following statement:

System.out.println(allPoints[1].getAllVisits(1).getDays());

Construct the method calculateTotalPoints(), in the Points class, which will calculate and return the total number of points awarded so far in the current year.

State the output given by the following statement:

System.out.println(allPoints[0].getBonusPoints());

State how an individual object can be identified using this array.

The attribute statusNow is assigned its correct value at the beginning of every year for existing members. It cannot be changed during the year.

Construct the method isGold() in the Points class, which will return whether the current status is “Gold”.