COMPUTER SCIENCE CHAPTER 1 - PROGRAMMING

Question 1

data type

Answer 1

data that we use and store in computer programs that come in various shapes and sizes

Question 2

data types

Answer 2

-integer
-real/double
-boolean
-character
-string
-records
-arrays
-date/time
-pointer/reference

Question 3

primitive data type

Answer 3

-supported by all languages
-any basic data type provided by a language as a foundational building block

Question 4

composite data type

Answer 4

built by combining other data types

Question 5

integer:

Answer 5

-any positive or negative whole number

Question 6

real/double

Answer 6

-decimal / fractional numbers

Question 7

boolean

Answer 7

-value which is either true or false

Question 8

pointer/reference

Answer 8

a way of storing memory address

Question 9

string

Answer 9

-sequence of characters

Question 10

character

Answer 10

-single number or letter

Question 11

user defined data type

Answer 11

derived from existing data types in order to create a customised data structure,, ensures it is memory efficient

Question 12

programming concepts:

Answer 12

-variable declaration
-constant declaration
-assignment
-iteration
-selection
-subroutine

Question 13

variable declaration:

Answer 13

-creating a variable type and giving it a name or sometimes a data type

Question 14

constant declaration:

Answer 14

-same as variable declaration but when creating the constant the value of it doesn’t change while the program is running

Question 15

assignment:

Answer 15

-giving a constant or variable a value

Question 16

iteration:

Answer 16

-repeating a instruction can be definite or indefinite

Question 17

selection:

Answer 17

-comparing values and choosing a action based on the values

Question 18

subroutine:

Answer 18

-block of code containing a set of instructions that can be called from other parts of the program

Question 19

definite iteration:

Answer 19

-loop repeats for a specific number of times

Question 20

indefinite iteration:

Answer 20

-block of code only repeats as long as the condition is true

Question 21

nesting:

Answer 21

-when one structure is placed within another to create a more complex structure

Question 22

arithmetic operations:

Answer 22

-addition
-subtraction
-multiplication - *
-division - /

Question 23

relational operations:

Answer 23

-used to compare 2 values
-equal to - ‘=’
-not equal to - ‘!’
-less than - ‘<’
-greater than - ‘>’
-less than or equal to - ‘<=’
-greater than or equal to - ‘>=’

Question 24

boolean operations:

Answer 24

-NOT ,, ! , opposite of a boolean value
-AND ,, && , product of 2 boolean values
-OR ,, ||, sum of 2 boolean values
-XOR - true if only one of 2 values is true

Question 25

variables

Answer 25

can change the value during the execution of a program

Question 26

constants

Answer 26

value cannot be changed once assigned

Question 27

advantages of using constants

Answer 27

-can be given identifier names making it easier for a human to understand -when updating a value constants only need updating once

Question 28

string handling operations:

Answer 28

-length -position -sub string -concatenation -character to character code -character code to character -string to integer -string to float -integer to string -float to string

Question 29

length:

Answer 29

returns the number of characters in a specified string

Question 30

position:

Answer 30

returns the position of a specified character within a string

Question 31

sub string:

Answer 31

given a starting position and a length so returns the portion of a string

Question 32

concatenation:

Answer 32

joining 2 or more string together to form a new longer string

Question 33

character to character code:

Answer 33

returning the character code which corresponds to a specified character

Question 34

character code to character:

Answer 34

returning the character represented by a given character

Question 35

random number generation:

Answer 35

-built in function takes a value and uses a series of mathematical operations to arrive at a number

Question 36

exception

Answer 36

thrown when a error occurs in a program code

Question 37

parameters

Answer 37

used to pass data between subroutines within programs , specified within brackets after a subroutine is called

Question 38

local variables

Answer 38

variable that can only be accessed from the subroutine within which it is declared

Question 39

==

Answer 39

compare 2 value sin a condition

Question 40

global variables

Answer 40

can be accessed from any part of the program

Question 41

=

Answer 41

assigning a value

Question 42

+=

Answer 42

increases a variable by a set amount

Question 43

-=

Answer 43

decreases a variable by a set amount

Question 44

for loops

Answer 44

have a start and end

Question 45

creating a record

Answer 45

-define the record structure , what fields will be in it -declare variable or array to use with the record -assign and retrieve data from the variable record

Question 46

while loop

Answer 46

can loop forever

Question 47

array

Answer 47

allows us to store multiple variables of the same type under a single identifier

Question 48

record

Answer 48

way of storing multiple variables under a single identifier

Question 49

string manipulation

Answer 49

way of scanning, checking , updating , converting strings in various ways

Question 50

subroutine

Answer 50

-block of code given a unique, identifiable name within a program

Question 51

procedure

Answer 51

-takes in zero, one or more parameters and performs a set task

Question 52

function

Answer 52

-block of code that takes in zero,one or more parameters -returns a value

Question 53

advantages of using subroutines:

Answer 53

-programs are easier to write -programs are easier to debug -functions can be grouped into libraries for easy reuse across multiple programs -programs are easier to test

Question 54

parameter

Answer 54

named variable defined in a function or method signature that acts as a placeholder for input data

Question 55

local variables:

Answer 55

-usually declared inside subroutines -accessible by only that subroutine -created when the subroutine is called -destroyed when subroutine ends

Question 56

global variables:

Answer 56

-declared at the top of the program outside of any subroutine usually -accessible throughout the program -created when program starts -destroyed when program ends

Question 57

stack frame

Answer 57

- stores all essential information for a single subroutine -allows program to know where to return to -allows programto restore the values of any local variables and parameters when it returns

Question 58

before calling another subroutine the system needs to:

Answer 58

-construct a stack frame -add a return address to the stack frame -add any local variables to the stack frame -push the completed stack frame on to the stack

Question 59

recursion

Answer 59

when a subroutine calls itself from within its own subroutine

Question 60

recursive subroutine should :

Answer 60

-contain a stopping condition (base case) -for any input value other than the stopping condition the subroutine should call itself(recursion) -stopping condition should be reachable within a finite number of times

Question 61

factorial of a number:

Answer 61

-for a positive number it is the product of all the positive integers less than or equal to n -n! -e.g. 5! =5 x 4 x3 x 2 x 1 =120

Question 62

paradigm

Answer 62

example of a way of doing things

Question 63

types of imperative languages:

Answer 63

-procedural programming -object orientated programming

Question 64

procedural programming

Answer 64

-where a program is built from one or more subroutines

Question 65

object orientated programming

Answer 65

-based on organising software design around objects rather than functions

Question 66

procedural programming details:

Answer 66

-features include sequence, selection and iteration -data is stored in local or global variables and can be accessed by other parts of program without passing a parameter -structure included procedures and functions -program logic is expressed in a series of procedure calls

Question 67

object oriented programming details:

Answer 67

-features consist of sequence, selection, iteration, inheritance, classes , objects , encapsulation -data is stored in attributes and concealed from other parts of the program via encapsulation -program structure consists of classes, methods and instances -program logic is based on models and behaviours

Question 68

problem decomposition:

Answer 68

-taking a large problem and breaking it down into several smaller problems

Question 69

step wise refinement/top down modular design:

Answer 69

-way to tackle problem decomposition

Question 70

advantages of having a structured approach :

Answer 70

-program is easier to read and understand -reduces the chance of errors and bugs as each function can be tested individually -changes can be made to one function without affecting others -enhances productivity and efficiency for programmer -improves reusability of the program as functions can be reused for different purposes

Question 71

object oriented programming(OOP):

Answer 71

-attempts to group information,data or related code into structured items known as objects

Question 72

objects - OOP:

Answer 72

-responsible for its own data and operations performed on that data -interact with each other by sending or receiving messages

Question 73

sections of classes:

Answer 73

-name of class -attributes of the class -methods of the class

Question 74

attributes - OOP:

Answer 74

- variables belonging to an object or class and containing information about their properties or characteristics

Question 75

methods-OOP:

Answer 75

-a procedure associated with the class that allows you to access or change its attributes

Question 76

class:

Answer 76

-a blueprint or template used to create specific objects

Question 77

instantiation:

Answer 77

-process of creating a object from a class template, where each object has its own attributes, methods and class template -when a object is created constructor sets up the new object and takes the values you give it and stores them inside the object

Question 78

constructor method:

Answer 78

-designed to initialise a new object instance when it is created

Question 79

inheritance:

Answer 79

-where a new class (child class) is derived from a existing class (parent class), inheriting its attributes and methods

Question 80

benefit of inheritance:

Answer 80

-can quickly and easily reused the code from the parent class and extend its attributes and methods without affecting the original code

Question 81

overriding:

Answer 81

-when you call a method from a object that shares the same name as a method further up the class tree

Question 82

encapsulation

Answer 82

-bundles the attributes and methods and restrict direct access to them -used to hide values or the internal state of a object, preventing direct access from unauthorised parties -helps keep data related to a object safe

Question 83

polymorphism:

Answer 83

situations in which something occurs in several different forms

Question 84

2 main types of polymorphism:

Answer 84

-static -dynamic

Question 85

static polymorphism:

Answer 85

-allows you to implement multiple methods of the same name but with different parameters within the same class

Question 86

static polymorphism, parameter sets must differ in at least one of these:

Answer 86

-different number of parameters -types of parameters need to be different -need to expect the parameters in a different order

Question 87

dynamic polymorphism:

Answer 87

-within a inheritance hierachy, a subclass can override a method of its superclass, enabling the developer of the subclass to customise or replace the behaviour of that method

Question 88

association

Answer 88

-relationship between two separate classes where one class uses or interacts with another

Question 89

aggregation

Answer 89

-more specific form of association -class contains or has many other classes, but those other classes can exist independently of the main class.

Question 90

composition

Answer 90

-stronger form of association -contained classes have a strong dependency on container class as if it is destroyed all container classes are too

Question 91

3 design principles of object orientated programming:

Answer 91

-favour composition over inheritance -encapsulate what varies -program to a interface not implementation

Question 92

why favour composition over inheritance:

Answer 92

-allows for greater flexibility -its less rigid than relationships that exist under inheritance -a object may be made of several other objects but in real life it does not make sense to say its inherited its characteristics

Question 93

why encapsulate(sum up) what varies:

Answer 93

-reduces need for testing and maintenance -designers should take properties and methods and sub divide them into as many classes as required to reflect real life scenarios

Question 94

why program to a interface not implementation:

Answer 94

-focus on what the code is doing instead of how its doing it -can change things more easily -code is more reusable

Question 95

interface

Answer 95

-declaration of capability -no actual code implemented