Thinking ahead

A linked list data structure is designed using object-oriented programming.

The design includes two classes called node and linkedList.

Describe the features of a linked list data structure.

The class design for node is shown here.

new() is the constructor method. The constructor method takes a parameter and assigns this to the value attribute.

The method getNextNode() returns the attribute nextNode.

Write the method getNextNode() using pseudocode or program code.

The method setValue() takes an integer as a parameter and assigns this to the attribute value

Write the method setValue() using pseudocode or program code.

The class design for linkedList is shown here.

new() is the constructor method. The constructor initialises the attribute headNode to a null value.

Write the constructor method using pseudocode or program code.

The class design for node and linkedList are shown again here for your reference.

The method getValue() will return the value of a node. The method getNextNode() will return the next node to be accessed in the linked list.

The method outputList() traverses the linked list starting at the node headNode. The method joins the data in each node and returns it.

Complete the method outputList() using pseudocode or program code.

The method insertNode() will insert a new node into the linked list.

The method accepts an integer as a parameter, creates a new node with that data and inserts it into the linked list, e.g. insertNode(8) creates a node object with the data 8 and adds it to the linked list.

The program needs to store the following data items in the linked list in the order they are given: 10 25 39

The program then needs to output all of the data in the list using the appropriate method.

Write an algorithm using pseudocode or program code to:

• create a new linkedList object with the identifier createList

• insert each of the data items into the linked list (10, 25, 39)

• output the content of the linked list.

A new method is needed to remove a node from the linked list. The method needs to take the data to remove as a parameter and then find this data in the linked list before removing the node.

Describe the steps that this method will need to follow and the decisions that need to be made in the method to remove the correct node.

The program developer made use of computational methods when designing the object-oriented programming solution. One computational method is divide-and-conquer.

Identify three other computational methods that the program developer could have used.

* This program uses classes and objects to create a linked list.

An alternative method is creating a 2-dimensional array. In this design the first index stores the data and the second element stores the index of the next data item. Array elements not currently used are also linked together to form a chain of empty values to identify where the next data item can be inserted.

Compare the two different methods of creating a linked list that have been described.

You should include the following in your answer:

• the features of both methods including the reusability of program components

• benefits and drawbacks of both methods in this program

• a conclusion evaluating the efficiency of both methods when designing a program that needs

a linked list.

A programmer has designed a program that includes a reusable program component.

The reusable program component is a function called isInteger(). This will take a string as an argument and then check that each digit is between 0 and 9. For example if 103 is input, it will check that the digits 1, 0 and 3 are each between 0 and 9.

The asc() function returns the ASCII value of each digit. For example asc("1") returns 49.

The ASCII value for 0 is 48. The ASCII value for 9 is 57.

Identify one identifier used in the function isInteger().

Give the line number where the branching (selection) construct starts in the function isInteger().

Give the line number where the iteration construct starts in the function isInteger()

Describe the purpose of the following lines in the function isInteger().

Line 03........

Line 04........

Line 09........

Give two reasons why reusable program components are used in programs.

The programmer will use abstraction to produce the program interface to represent the garden.

Give two different examples of how abstraction has been used to produce the layout of the garden.

Explain the need for abstraction in the production of this program.

The user needs to input data into the program to set up their garden layout.

Identify three pieces of data that the user may input into this program.

The program is to be built using object oriented programming.

All items that can be added to the garden are declared as instances of the class GardenItem

The class has the following attributes:

The constructor method sets the attributes to values that are passed as parameters.

Write pseudocode or program code to declare the class GardenItem and its constructor. All attributes should be private and initialised through the constructor (e.g. daisies =

new GardenItem("Flowerbed",2,1)

The trees in the garden layouts are defined by the class Tree. This class inherits from GardenItem.

The class Tree has the additional attributes: height, sun, shade.

If sun is true then the tree can grow in full sun, if it is false then it cannot.

If shade is true then the tree can grow in full shade, if it is false then it cannot.

The length and width of a tree are the same. Only one value for these measurements is passed to the constructor.

Write an algorithm, using pseudocode or program code, to declare the class Tree Declare all attributes as private.

The Common Oak is a type of tree. It has a maximum height, length and width of 40 m. It can grow in sun and shade.

Write a statement, using pseudocode or program code, to declare an instance of tree for the Common Oak. Give the object the identifier firstTree.

The classes GardenItem and Tree use get and set methods to access and alter their private attributes.

Write the get method getItemName and set method setItemName for class GardenItem. The set method takes the new value as a parameter.

Do not write any other methods, or re-declare the class.

* The programmer is designing the program to make use of caching and re-useable components.

Explain and evaluate the use of caching and re-useable components in the design of the garden program.

A program stores entered data in a binary search tree.

The current contents of the tree are shown:

Complete the diagram to show the contents of the tree after the following data is added:

England, Scotland, Wales, Australia

Show the order of the nodes visited in a breadth first traversal on the following tree.

A pseudocode algorithm is written to search the tree to determine if the data item “Sweden” is in the tree.

The function currentNode.left()returns the node positioned to the left of currentNode

Complete the algorithm.

The algorithm needs to be used in different scenarios, with a range of different trees.

Identify two preconditions needed of a tree for this algorithm to work.

A company merger is joining five e-commerce retailers under one company, OCRRetail. Each retailer has a different sales system and OCRRetail wants to develop one computer system that can be used by all the retailers.

Mary’s software development company has been employed to analyse and design a solution for the company.

Two computational methods (techniques used to solve a problem using computational thinking) that Mary will use are problem recognition and decomposition.

State what is meant by problem recognition and decomposition.

State one additional computational method.

Mary plans to use data mining to generate information about OCRRetail’s customers. Mary will use this information to benefit the company.

Define the term ‘data mining’.

Identify two pieces of information that data mining could provide OCRRetail about sales, and state how OCRRetail could make use of this information.

Mary has developed the program and is considering using performance modelling before installing the system.

Define the term ‘performance modelling’.

Identify one way performance modelling could be used to test the new system.

Mary created the program as a series of sub-programs that can be reused.

Describe one benefit of Mary creating reusable program components.