Computer Science Exam Questions Flashcards

Question

An XOR gate is shown below. Complete the truth table for XOR. (https://cdn.discordapp.com/attachments/860926934221062177/971409764414259210/IMG_6223.jpg)

Answer 1

Complete the truth table for XOR. | https://cdn.discordapp.com/attachments/860926934221062177/971409861671809114/IMG_6224.jpg

Answer 2

Complete and use the Karnaugh map below to simplify the expression above (https://cdn.discordapp.com/attachments/860926934221062177/971410806363287602/IMG_6225.jpg) Simplified Expression = B v (¬C /\ ¬D)

Answer 3

``` tagStartPos = 0 insideTag = false i = 0 while i < htmlCode.length if htmlCode.substring(i,l) == " ```

Answer 4

(a) state why the table above is not in the Third Normal Form. It is not in the third normal form as there is a repeated value in Sort Code & Branch Name (b) Explain how the database could be put into Third Normal Form. The database could be put into Third Normal Form by making sure there are no repeated entries, and that each entry is under another thing which it is unique, for instance, As the Acc No, is Unique to the customer, and each customer is given a unique Customer ID, Customer ID would become a primary key, while Forename, Surname and Acc no would become entries underneath it, while as the Sort Code depends on the Branch Name, the Sort Code would become a primary Key, while Branch Name would be an entry underneath it. It would now be in second normal form. To put it into Third Normal Form, one of the entries which are both Primary Keys would have to become a foreign key for the other, linking them together, to do this, you would split the two groups into three, one group consisting of Customer ID as the Primary Key, with Forename and Surname as the entries below it, Another group consisting of Customer ID and Acc No, with Customer ID being a foreign key for the past Customer ID table and Acc No being a primary key, after this, there would also be a table consisting off Acc No, Sort Code and Branch Name, With Sort code being the primary Key but Acc No being a foreign key to link it to the others

Answer 5

Discuss how the bank can ensure the accuracy of its data and the importance of doing. There are a few things the bank needs to do to keep data accurate, these make sure that the data is consistent, isolated, durable, locked when not in use, has referential integrity, have redundancies, accurate in the first place, have security measures to prevent tampering as well as be validated and verified. making sure the data is consistent means that the transaction should only change the database according got the rules of the database Making sure the data is isolated means that each transaction shouldn't affect/overwrite other transactions concurrently being processed Making sure the data is durable means that once a transaction has been started it remains no matter what happens what is meant by being locked when not in use is that if one transaction is amending a record, no other transaction should be able to until the first transaction is complete By having referential integrity, it is meant that changes to data in one table must take into account data in linked tables Data having redundancies means that if part of a database is lost it can be recoverable elsewhere By the data being verified and validated, it means that the data should be automatically checked and checks done if the data entered matches the original

Answer 6

State whether a binary search or a linear search would be the most appropriate method to search for a specific card, and justify your answer. Search Method: Linear Search Justification: small and unordered, binary searches are more suited for large, ordered datasets.

Answer 7

(a) Identify the parameter that is passed to this procedure Item(1) (b) Describe the logical decisions that are made It either sets the queue_full to true or adds the next item to the front (c) (i) The algorithm contains a logic mistake. Explain what the mistake is The mistake made is that it adds the object to the wrong area, and should instead be added to the rear of the list ``` (ii) Rewrite the algorithm to correct the mistake if front == max then queue_full = true else rear += 1 queue[rear] = item end if ```

Answer 8

i. Describe the use of local variables • Used only in specific routines or areas of code • cab be used as parameters • data lost at end of the module ii. State two features of global variables that distinguish them from local variables 1. Can be used throughout the code with the entered value remaining constant 2. announced at the start of code outside any routines or procedures

Answer 9

Compare a procedure with a function | A function returns only one value and can run whenever called, a procedure is a subsection of code

Answer 10

(a) The programmer will use abstraction to produce the program interface to represent the garden (i) Give two different examples of how abstraction has been used to produce the layout of the garden 1. Key items in the garden have been included, minor items have been ignored 2. removal of unimportant things, or things which are easily inferred to make visualisation easier (ii) Explain the need for abstraction in the production of this program Abstraction is needed in the creation of this program because: to highlight important details, remove minor details which aren't needed as well as decrease the storage space which the minor details would take up (iii) 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 1. Items in garden 2. Location of items in the garden 3. Size of items in the garden ``` (b) 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 ``` (https://cdn.discordapp.com/attachments/860926934221062177/971453446471446588/IMG_6234.jpg) ``` (i) 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 conductor (e.g. daisies = new GardenItem("Flowerbed",2,1) ). ``` ``` class GardenItem Private ItemName Private length Private width public procedure new(pItemName, pLength, pWidth) ItemName = pItemName length = pLength width = pWidth end procedure end Class ``` ``` (ii) 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, and shade. If the 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 ```

Answer 11

``` (a) Lizard is a class. Describe what is meant by a class A template defining methods and attributes used to make objects ``` (b) Identify an attribute in the lizard class. Speed / mass / size ``` (c) (i) Describe what is meant by the term inheritance Inheritance is when a class takes on the methods and attributes of a parent class. The inheriting class may override some of these methods/attributes and may have added extra methods and attributes of its own. ``` (ii) Explain one way the game's developers might use inheritance for Livid Lizards. Inheritance could be used for Livid Lizards by having multiple lizards which inherit the methods and attributes of one base lizard, in order to create different types of lizards, which would have different attributes since the base stats of the lizard can be overwritten or modified to suit different lizards (d) The game uses a 2D graphics library. Explain why a linker wound needs to be used after compilation A linker would be needed to be used after compilation as without it the 2D graphics library and the main code wouldn't be able to communicate together, this would mean that the lizards would not have any attributes. Also as the library is not on the computer, after compilation if the linker is present, the 2D graphics library would not need to be downloaded by the user.

Answer 12

(a) Two equal (unsigned) integers, shown below, are added together. Calculate the result, showing your working (00010101 + 00010101) = 00101010 (b) State which bitwise manipulation on 00010101 would have achieved the same result as the calculation on part (a). One shift to the left (c) Convert the denary number -52 into an 8-bit binary number using two's complement (d) Describe why Two's complement may be preferable to sign and magnitude. (e) Using floating-point representation with 4 bits for the exponent and 4 bits for the mantissa, add together the following floating-point binary numbers and write the answer as a normalised floating-point number with a 4-bit mantissa and a 4-bit exponent 0110 0010 and 0100 0011

Computer Science Exam Questions Flashcards

(36 cards)