2.1 Algorithms

Question 1

What is Abstraction?

Answer 1

Process of removing unnecessary details and including only the relevant details

Question 2

What is Decomposition?

Answer 2

Breaking a complex problem into smaller more manageable parts

Question 3

What is Algorithmic Thinking?

Answer 3

Creating a step by step solution to a problem

Question 4

What are the 2 types of searching algorithms?

Answer 4

Binary and Linear search

Question 5

What are the advantages of a Linear Search?

Answer 5

Simple
The list doesn’t need to be ordered
Easy to program

Question 6

What are the disadvantages of a Linear Search?

Answer 6

Not efficient

Takes time with a lot of data

Question 7

What are the advantages of a Binary Search?

Answer 7

More efficient than a linear search

Question 8

What are the disadvantages of a Binary Search?

Answer 8

Only works on an ordered list

Question 9

How does linear search work?

Answer 9

Checks each item in the list one by one until it finds what it is looking for

Question 10

How does binary search work?

Answer 10

Finds the middle item in an ordered list
By doing n+1/2
Compares the item to the middle item
So it knows where to look in the first half of the second half
Repeats until the item is found

Question 11

What is a sorting algorithm?

Answer 11

Sorts items into an ordered list

Question 12

How does a bubble sort work?

Answer 12

Checks the first 2 items in a list
Swaps them if they are in the wrong order
Moves to the next items and Repeats
Moves through the entire list again
Until ordered

Question 13

How does a merge sort work?

Answer 13

Finds the middle item by (n+1)/2
Splits the list in half
Repeats until items are paired
Each time the sub-list are paired 
They are sorted into the correct order

Question 14

How does an insertion sort work?

Answer 14

Looks at 2nd item in the list and compares it to the items that are in front of it
Then inserts it into the right place correctly
It is Quick for sorting small lists

Question 15

What is the shape of the input box?

Answer 15

Parallegoram

Question 16

What is the shape of a decision making?

Answer 16

Diamond

Question 17

What is the shape of the process?

Answer 17

Rectangle

Question 18

What does the lines show?

Answer 18

The control passing betweens the connected shapes

Question 19

How do you output an statement?

Answer 19

Print(“hello”)

Question 20

How do you do a for loop in OCR Reference language

Answer 20

For i = 0 to 7
…
next i

Question 21

What are the comparison operators?

Answer 21

== Equal to
!= Not equal to
< Less than
<= Less than or equal to
> Greater than
>= Greater than or equal to

Question 22

What does 12 MOD 5 give?

Answer 22

2 - Because the MOD function always returns the remainder

Question 23

What does 12 DIV 5 give?

Answer 23

2 - DIV functions returns how much a number goes into another number - excluding remainders

Question 24

How do you do an IF - THEN - ELSE in OCR Exam Reference Language?

Answer 24

If x== 6 then
...
elsif .. then
..
else
...
endif

Question 25

How do you do an CASE SELECT or SWITCH?

Answer 25

Switch x:
  case "a":
   ....
  case "b":
  ...
  default: (Same as an else equivalent)
endswitch

Question 26

How do you get a length of a spring?

Answer 26

Variable.length

Question 27

How do you get “put” from subject = “ Computer Science”

Answer 27

subject.substring(3,3))

will start at position p - because the string starts at the 0th character

then count the character its on and go 2 along

which will print out put

Question 28

How do you make a string in all upper cases?

Answer 28

String.upper

Question 29

How do you make a string in all lower cases?

Answer 29

string.lower

Question 30

What is an example of a procedure?

Answer 30

procedure name(..)
…
endprocedure

Question 31

What is an example of a function?

Answer 31

function name(..)
  ...
  return ...
  endfunction

Question 32

How do you call a function?

Answer 32

function(parameters)

Question 33

How do you call a procedure?

Answer 33

procedure(parameters)

Question 34

How do you establish an array?

Answer 34

array name[5] - example

array name[number of boxes]

Question 35

How do you declare a 2D array?

Answer 35

For example

array board[8,8]

Question 36

How do you make a random number?

Answer 36

myVariable = random(1,6)

Question 37

How do you open a file?

Answer 37

For example:

myFile = open(“sample.txt)

Question 38

How do you close a file?

Answer 38

myFile.close()

Question 39

How do you read/write a file?

Answer 39

Myfile.readLine( )

Myfile.writeLine(..)

Question 40

How do you end a file/ create a file?

Answer 40

myFile.endOfFile()

newFile()

Question 41

What are syntax errors?

Answer 41

Errors which break the grammatical rules of the programming language

Stop it from being run

Question 42

What are logic errors?

Answer 42

Errors that produce an unexpected output

On their own they won’t stop a program from running

Question 43

What are the advantages of constants?

Answer 43

Can make a program easier to read
Compiler can optimises the code
Less chance of errors

Question 44

What is a sequence?

Answer 44

Executing instructions one after another

Question 45

What is selection?

Answer 45

Program branching depending on the condition

Question 46

What is iteration?

Answer 46

Looping - repeating sections of the code

Question 47

When are FOR loops used?

Answer 47

Number of iterations needed is known ahead of the iteration executing

Question 48

When are WHILE loops used?

Answer 48

When the number of iterations is not known