| Date | November 2017 | Marks available | 1 | Reference code | 17N.2.SL.TZ0.11 |
| Level | SL | Paper | 2 | Time zone | no time zone |
| Command term | Construct | Question number | 11 | Adapted from | N/A |
Question
The global variable tables is declared as follows:
Payment[] tables = new Payment[50];
The indices in this array represent the table number, so tables[1] is a Payment object for the customers occupying table number 1.
The driver (main) class contains the following code. Note: You can assume that all appropriate accessor and mutator methods have been included in their respective classes.
tables[1] = new Payment();
tables[2] = new Payment();
FoodItem a = new FoodItem("f102", 2);
FoodItem b = new FoodItem("f100", 1);
DrinkItem c = new DrinkItem("d102", 3);
tables[1].addFoodItem(a);
tables[1].addFoodItem(b);
tables[2].addDrinkItem(c);
tables[2].addDrinkItem(new DrinkItem("d103",1));
System.out.println(tables[1].getFiCount());
System.out.println(Payment.getFoodTax());
System.out.println(tables[2].getDi(1).getItemCode());
The price of each item is stored in an object of the Item class.
The class is outlined below:
public class Item
{
private String code; // item code
private String name; // item name
private double price; // unit price before tax
// all accessor, mutator and constructor methods are included
}
All of the objects in this class are held in the global array pl according to the following declaration:
Item[] pl = new Item[200];
Note: The number of objects held in this array will change from week to week.
The method findPrice(Item[] pl, String c) in the Payment class looks up and returns the price of the item with code c.
State the output after this code is executed.
Construct statements, in code, that will print out the following: The number of drink items ordered by table 40.
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 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.
Markscheme
Award [1] for each correct value.
2;
0.2;
d103;
System.out.println(tables[40].getDiCount());
Allow variations of the get method name
Note: Ignore minor syntax errors.
System.out.println(tables[2].getFi(2).getItemCode());
Allow variations of the get method name
Note: Ignore minor syntax errors.
Award marks as follows up to [6 max].
Award [1] for correct initialization.
Award [2] for loop that checks entries, but has early exit.
Award [1] for a loop that checks all 200 entries with no early exit.
Award [1] for correct assignment.
Award [1] for correct comparison.
Award [1] for correct return value.
Award [1] for both the assignment and comparison IF get methods are not used.
public static double findPrice(Item[] pl, String c)
{
int x = 0;
double price = 0.0;
boolean found = false;
while(!found)
{
if ((pl[x].getCode()) == c)
{
price = pl[x].getPrice();
found = true;
}
x++;
}
return price;
}
Award marks as follows up to [7 max].
Award [1] for correct method header.
Award [1] for correct initialization.
Award [1] for correct loop.
Award [1] for finding item code.
Award [1] for use of findPrice method.
Award [2] for the calculation if completely correct, award only [1] if taxes are wrong and/or no use of accessor.
Award [1] for consideration of both food and drink objects (whether correct or not);
public double calculateBill(Item[] pl)
{
double total = 0.0;
for(int x = 0; x < fiCount; x++)
{
String c = fi[x].getItemCode();
double price = findPrice(pl,c);
total = total + fi[x].getQuantity()*price*(1 + foodTax);
}
for(int y = 0; y < diCount; y++)
{
String c = di[y].getItemCode();
double price = findPrice(pl,c);
total = total + di[y].getQuantity()*price*(1 + drinkTax);
}
return total;
}
