extraa

Question 1

Why close files?

Answer 1

When a file is “opened,” the operating system marks the file as locked, generally so it can’t be deleted by other processes while it’s being used. myFile.close() undoes the lock, allowing the operating system and other processes to do what it wishes with the file. It also releases any system resources associated with the stream.

Question 2

What happens if a parameter is passed by value?

Answer 2

a copy of the variable is passed to the subroutine where it is treated as a local variable thus protecting it from being changed by the subroutine but also using additional memory space. It is destroyed when the subroutine has completed.

Question 3

What happens if a parameter is passsed by reference

Answer 3

the reference to the memory location of the variable itself is passed Therefore if the value of the variable is changed, it remains changed after the subroutine ends. A literal value can’t be passed by reference obviously as it has no reference (more applicable to recursive subroutines).

Question 4

If it is not stated will parameters be passed by value or by reference

Answer 4

By value

Question 5

How do you do by value and by ref?

Answer 5

procedure calculateTotal(x:byVal, y:byRef)

Question 6

What is encapsulation?

Answer 6

All of the object’s attributes are contained and hidden in the object by giving them the private access modifier. They are accessed through public getter and setter methods.

Question 7

What is instantiation?

Answer 7

The process of creating an instance of a class.

Question 8

What is a class?

Answer 8

A blueprint for creating an object.

Question 9

What is an access modifier?

Answer 9

For example public and private which can be applied to attributes and methods in the class. Private means the attribute or method can not be accessed by code in another class while public means it can.

Question 10

What is an atribute?

Answer 10

A specific piece of data representing a particular characteristic of an object.

Question 11

What is a constructor?

Answer 11

A method that is called when creating an instance (object) of a class.

Question 12

What is an object?

Answer 12

Instance of a class

Question 13

What is OOP?

Answer 13

A programming paradigm which classifies real world objects into classes and encapsulates the object’s attributes and behaviours.

Question 14

What are methods?

Answer 14

for example getters and setters and other subroutines that define the behaviour of the object.

Question 15

What is inheritance?

Answer 15

A mechanism that allows an instance of a class to inherit attributes and methods from another class (the superclass/parent class). It can also have methods/attributes of its own.

Question 16

Subclass

Answer 16

A class that inherits from another class is called a subclass (also a derived class, extended
class, or child class).

Question 17

Superclass

Answer 17

The class from which the subclass inherits from is called a superclass (or parent class).

Question 18

What is polymophism?

Answer 18

(many forms) The ability of an entity such as a variable, operator, method or object to have more than one form. There are multiple types of polymorphism. In OOP, the ability for classes that share a common superclass to have different implementations of a method with the same name is one example. This is called overriding.

Question 19

What are the advantages of inheritence?

Answer 19

reusability and readability. When child class inherits the properties and functionality of parent class, we do not need to write the same code again in child class. This makes it easier to reuse the code, makes us write the less code and the code becomes much more readable

Question 20

What are the disadvantages of inheritence?

Answer 20

When you choose to inherit from another class, you have coupled the two classes. What will happen if someone extends the base class? What will happen if someone changes the base class to inherit from another class? Your class may now have acquired attributes and methods that you are not aware of.

Question 21

What is the idea of an insertion sort?

Answer 21

Repeat the following for each item in the list, excluding the first
Remember the current item as the key
Move every item before the key that is bigger than it forward
Place the key item before these larger items

Question 22

Advantages of insertion sort?

Answer 22

Advantages
Easy to implement
Good for small data sets that are almost sorted
Insertion sort generally performs quicker than bubble sort and is therefore preferable

Question 23

Disadvantages of insertion sort

Answer 23

Disadvantages
Does not scale well so is not good for large data sets

Question 24

What is a bit shift?

Answer 24

An operation that moves the bits in a byte, nibble etc by a determined number of places to either the left or right.

Question 25

Bitwise AND operator

Answer 25

A operation that takes two equal-length binary representations and performs the logical AND operation on each pair of the corresponding bits.

Question 26

Bitwise OR operator

Answer 26

A operation that takes two equal-length binary representations and performs the logical OR operation on each pair of the corresponding bits.

Question 27

Bitwise XOR operator

Answer 27

A operation that takes two equal-length binary representations and performs the logical XOR operation on each pair of the corresponding bits.

Question 28

Mask/bitmask

Answer 28

Data that is used with a bitwise operator. Using a mask, bits in a byte, nibble, etc. can be set either on or off, or inverted in a single bitwise operation

Question 29

Left shift

Answer 29

When shifting left, the most-significant bit is lost and a 0 * fills the least significant bit.

Question 30

Right shift

Answer 30

When shifting right, the least significant bit is lost, and a 0 * fills the most significant bit.

Question 31

What is a bit mask?

Answer 31

A bit mask is data that is used with a bitwise operato

Question 32

What is second normal form

Answer 32

Non-key fields must depend on every part of the primary key

Question 33

What is third normal form?

Answer 33

There are no non-key fields that depend on another non-key field

Question 34

First principle of the misuse act?

Answer 34

1. Unauthorised access to computer material.

Question 35

Second principle of the computer misuse act?

Answer 35

2. Unauthorised access with intent to commit or facilitate commission of further offences.

Question 36

Third principle of the misuse act?

Answer 36

3. Unauthorised acts with intent to impair, or with recklessness as to impairing, operation of computer, etc.

Question 37

name some principles of the data protection act

Answer 37

Storage Limitation - personal data must be kept for no longer than is necessary Lawful, fair and transparent - processing must be lawful, fair and transparent; For example, a speeding ticket - not unfair. Asking for consent to use photographs is lawful Accuracy - personal data must be accurate and kept up to date Purpose limitation - purposes of processing must be specified, explicit and legitimate Minimisation of data - personal data must be adequate, relevant and not excessive Integrity & Confidentiality - personal data must be processed in a secure manner Accountability - the controller shall be responsible for, and be able to demonstrate compliance