An object oriented system is implemented to organise further information about each worker’s attendance. Classes, objects, methods and attributes are used in this system.
State the meaning of each of the following terms:
Object
Method
Attribute
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Barney is writing a program to store data in a linked list. He is writing the initial program for a maximum of 10 data items.
Each node in the linked list has a data value and a pointer (to the next item).
A null pointer is stored with the value –1
Barney wants the nodes to be stored as objects using object-oriented programming. He designs the following class.
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The constructor assigns the parameters to the attributes to create an object
The class node, uses get methods and set methods.
Describe one difference between get methods and set methods.
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A supermarket uses an object-oriented approach to organise items that it offers for sale. Part of the class definition for the ItemForSale class is shown below.
class ItemForSale
public itemName
public price
public discount
…
endclassThe discount attribute represents a percentage discount on the price. The discount can be between 0 and 50 (inclusive). All new items for sale initially have a discount value of 0.
Write the constructor method for the ItemForSale class.
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A supermarket uses an object-oriented approach to organise items that it offers for sale. Part of the class definition for the ItemForSale class is shown below.
class ItemForSale
public itemName
public price
public discount
…
endclassWrite a line of code to create an object of type ItemForSale called mushypeas that has a name of “mushy peas” and a price of £0.89
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State the purpose of a constructor.
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Describe what is meant by inheritance with reference to these classes.
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A supermarket uses an object-oriented approach to organise items that it offers for sale. Part of the class definition for the ItemForSale class is shown below.
class ItemForSale public itemName public price public discount … endclass
Write the calculatePrice() method, which applies the percentage discount to the price and returns the new value.
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The supermarket has previously had issues with discounts being set as values above 50.
Explain how encapsulation could be applied to the ItemForSale class to stop this problem from occurring.
You are not expected to write any code in your answer to this question.
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Some items in the supermarket are only available through home delivery. These items are the same as ItemsForSale with the following exceptions:
the supermarket also stores the location of the stock
the percentage discount allowed is up to 75 rather than the standard 50.
Explain how inheritance can be used to implement the above requirements.
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Barney wants the nodes to be stored as objects using object-oriented programming. He designs the following class.
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The constructor assigns the parameters to the attributes to create an object.
Write an algorithm, using pseudocode or program code, to create the class node, its attributes and constructor.
You do not need to write the get and set methods.
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A business uses an array with the identifier wNames to store workers’ names. A variable with the identifier top is used to store the index of the last element to be added to the array, which is also the element which will next be removed.
wNames
0 | 1 | 2 | 3 | 4 | 5 | 6 |
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Kirstie | Martyn | Louise | Alex | Anna |
top
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An object oriented system is implemented to organise further information about each worker’s attendance. Classes, objects, methods and attributes are used in this system.
Each worker has a name and an attendance figure which can be between 0 and 100.
Write a definition for a fully encapsulated customer class, providing both get and set methods for all attributes. You do not have to write code for the constructor method.
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Barney would like his linked list to be part of a base program that is saved in a library. This means that it can be reused and changed by other programs.
Discuss the benefits of using different object-oriented techniques that Barney could use to achieve this.
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