Computing (Modular) CP1
January 2008
 (1.5 Hours)

[1] Data about students in a school are held in a computer system.

 

  
(i) Describe student data which would best be stored in each of the following data types:

 

  
  string data type; [1]
   
  integer data type; [1]
     
  boolean data type; [1]
     
  real data type; [1]
     
(ii) Draw a diagram to show data about the students which might sensibly be stored in a two-dimensional array.

 

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[2](a)(i) A line of computer code contains a calculation error, generating incorrect values when the program is run. What type of error is this?

 

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(ii) (I) What type of error occurs when a computer program unexpectedly stops (crashes) while running?

 

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  (II) Give one example of this type of error.

 

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(iii) (I) A computer program includes a line in which a command word is misspelled. What type of error is this?

 

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  (II) Give another example of this type of error.

 

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(b) Explain why careful version control is important when developing computer programs.

 

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[3] Some programming languages have certain features which are useful when developing web pages.

Describe two features which make such languages suitable for this purpose.

 

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[4] A computer system is being developed to replace an existing computer system for a bank.

 

  
(i) Describe two activities which should take place during the requirements analysis for this development.

 

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(ii) Describe two different types of documentation that will be produced for the new system and indicate who is most likely to read each type.

 

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(iii) Describe two different approaches which could be adopted to the changeover from the old system to the new system.

 

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(iv) Computer programs within the new system need to be maintained. Name two types of program maintenance and give an example of a situation where it might be appropriate in each case.

 

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[5] A binary search is used to search for the number 26 in the following array:  
 
11 14 24 26 36 41 41 43 48
 
(i) Why is this array suitable for a binary search?

 

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(ii) Name a type of search which is suitable when a binary search is not possible.

 

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(iii) Write down one possible order in which the numbers in the above array will be accessed to complete the search for 26 in a binary search.

 

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(iv) What should happen if a binary search is made for the number 45 in this array?

 

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[6](a) Describe the difference between applications software and systems software.

 

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(b) What is meant by the scope of a variable in a computer program?

 

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[7] A small firm sends letters to its customers. It does this by combining name and address data from one part of an integrated package into a standard letter produced in another part of the same package.

 

  
(i) What name is given to the operation when data is combined in this way?

 

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(ii) Which two parts of the integrated package would be useful for this?

 

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(iii) The firm uses macros while producing these letters. Explain what is meant by the term macro.

 

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[8] An Internet-based book-seller allows its customers to send an email, via its web-site, to make an enquiry about a book order already made, such as the expected delivery date. Staff at the company then email the customer with a response.

At the same time as making the enquiry, the customer has an opportunity to make a comment about the quality of the service the company provides. Any comments made are stored by the system.

The diagram below illustrates the situation described.

 

  
   
(i) Diagrams like these are often used in discussion with users. Give one reason why this is the case.

 

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(ii) What type of object does the following shape represent? [1]
 

 
     
(iii) Draw the shape used in the diagram to represent a process.

 

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(iv) Give a suitable name for the object shown as a in the diagram.

 

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(v) Give a suitable name for the object shown as b in the diagram.

 

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(vi) Give a suitable name for the object shown as c in the diagram.

 

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(vii) Give a suitable name for the object shown as d in the diagram.

 

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[9] A credit card company issues two types of credit card, a Gold Card and a Standard Card.
When a member of the public applies to the company for a credit card, the company makes a security check, then decides to do one of the following:
  • offer a Gold Card;
  • offer a Standard Card;
  • reject the application.

This decision depends on the applicant's income and whether or not they are a home-owner. The algorithm used is shown below:

 

  
 
Statement
1 input Income
2 input HomeOwner
3 if ((Income > 25,000) AND (HomeOwner = TRUE))
4   then output "Gold Card"
5   else if (((Income > 15,000) AND (HomeOwner = TRUE)) OR (Income > 20,000))
6     then output "Standard Card"
7     else output "Reject"
(a)(i) State what the output will be for a home-owner with an income of £13,000.

 

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(ii) State what the output will be for a home-owner with an income of £30,000.

 

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(iii) State what the output will be for a person with an income of £22,000 who does not own a home.

 

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(iv) State what the output will be for a home-owner with an income of £22,000.

 

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(b) The algorithm above is correct. However, it is accidentally entered incorrectly, so that the word "OR" in statement 5 is changed to "AND" as shown below:  
 
5   else if (((Income > 15,000) AND (HomeOwner = TRUE)) AND (Income > 20,000))
  One of the parts (a) (i) to (iv) now gives a different output. State which part gives a different output and write down what the output will now be.

 

 [2]
     
(c) The company decides to make a change to the (correct) algorithm so that statement 3 becomes:  
 
3 if (((Income > 25,000) AND (HomeOwner = TRUE)) OR (Income > 50,000))
  Why might the company have decided to make this change?

 

 [1]
     
 
[10] In the following question, additional credit (up to 3 marks) will be given if your answer demonstrates skill in written communication.

 

  
  A new computer program needs to be carefully designed and tested if it is to be successful.

One area where good design is essential is the human-computer interface (HCI). It is expected that many of those using the new system will be experienced computer users. Describe desirable HCI features, particularly those which would be helpful to experienced users.

Another important area is the testing of the new system. Describe the activities which should be carried out during testing.

 

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