PAPER 2 - Algorithms, Programming, Logic

Question 1

What is analysis

Answer 1

• abstraction, decomposition of the problem, identification of the problem

Question 2

What are the 4 main stages in the program development life cycle:

Answer 2

-ANALYSIS
- DESIGN
- CODING
- TESTING

Question 3

What is design

Answer 3

• decomposition, structure diagrams, flow charts, pseudocode

Question 4

What is coding

Answer 4

Writing program code + iterative testing

Question 5

what is testing

Answer 5

Testing program code with use of test data

Question 6

What is abstraction

Answer 6

• involves identifying the key parts of the problem
• removing any unnecessary detail to make it easier to
  solve

Question 7

What is the purpose of structure diagrams

Answer 7

• show structure of the problem, its subsections + links to other subsections

Question 8

What is decomposition

Answer 8

The breaking down of a complex problem into smaller, manageable parts which are easier to solve

Question 9

What are the 4 steps of decomposition

Answer 9

• identify the main problem
• identify the component part of input, processes, outputs and storage
• list main sub-problems, sub-systems , functions or tasks
• break these down into smaller sub- problems or sub-tasks , which can be completed separately

Question 10

In flow charts what is the symbol for input/output

Answer 10

Parallelogram

Question 11

Flow chart symbol for process

Answer 11

Rectangle

Question 12

Flow chart symbol for decision

Answer 12

Diamond

Question 13

Flow chart symbol for terminator

Answer 13

Oval

Question 14

What are the 5 data types

Answer 14

• integer
• real/float
• Boolean
• char
• string

Question 15

What is a real/float

Answer 15

number with a decimal point

Question 16

What is a Boolean

Answer 16

Either TRUE or FALSE

Question 17

What is a char

Answer 17

A single alphabetic or numeric character
E.g. A,#, @, 6, !

Question 18

What is a string

Answer 18

A sequence of one or more characterS
E.g. “yes”, “Hi John”

Question 19

Explain the difference between a variable and a constant.

Answer 19

• Variable – a storage container in memory that can hold information as a number, a person’s name or a whole sentence.
• Constant – a variable, once defined , it cannot be changed during execution of program, You cannot declare a value as a constant in python.
  E.g. Value that never, or rarely changed : pi, speed of light

Question 20

Pi = 3.142
Radius = float(input(“Enter radius”)
Circle_area = pi*(radius^2)
Print(Circle_area)
What is a variable and what is a constant

Answer 20

Variable = radius
Constant = Pi

Question 21

What is the assign symbol operator un psuedocode

Answer 21

<—

Question 22

WHILE….__

Answer 22

DO

Question 23

A <— 22 MOD 5
What is A?

Answer 23

2 (reminder)

Question 24

C <— 22 DIV 5

Answer 24

C = 4

Question 25

What is a sequence

Answer 25

**two or more statements** written and **executed one after the other in sequence**

Question 26

What is a selection statement

Answer 26

Selection stemmet comprises an **IF**or **CASE** stement and a **logical expression**.

Question 27

IF is what kind of statement

Answer 27

Selection statement

Question 28

What are the 3 iterations:

Answer 28

- FOR … NEXT - WHILE … ENDWHILE - REPEAT … UNTIL

Question 29

What is a nested if statement

Answer 29

An IF statement inside another IF statement : IF .. THEN ELSE IF … THEN ELSE ENDIF

Question 30

What is a CASE statement

Answer 30

CASE statement - allow one of several branches of code to be executes, depending on the value of a variabel

Question 31

Think of a CASE programme about member types

Answer 31

INPUT MemberType CASE OF MemberType "Junior" :EntryFee <—2.0 "Senior" :EntryFee <— 3.0 "Special" : EntryFee <— 0.0 OTHERWISE OUTPUT "Invalid member type" //Other conditions not net ENDCASE

Question 32

CASE …. ___________

Answer 32

OTHERWISE

Question 33

Name a count-controlled loop

Answer 33

FOR … NEXT

Question 34

Counter -

Answer 34

A counter is automatically incremented each time the loop is performed

Question 35

A code to print out numbers from 1 - 10

Answer 35

FOR Count <— 1 TO 10 OUPUT COUNT NEXT Count

Question 36

Code to print out numbers 2,5,8

Answer 36

FOR i <— 2 TO 10 STEP 3 OUPUT i NEXT i

Question 37

Example of a pre-conditioned loop

Answer 37

WHILE…DO….ENDWHILE

Question 38

What are pre-conditioned loops

Answer 38

Controlled by a Boolean condition white is checked **before** the loop is entered

Question 39

What are post-conditioned loops

Answer 39

Controlled by a Boolean condition white is checked **at the end** the loop is entered. therefore performed at least once

Question 40

Example of a post-conditioned loop

Answer 40

REPEAT….UNTIL

Question 41

Write a pseudocode algorithm which allows a user to input numeric scores and prints how many of them are over 100. The program allows the user to enter any number of scores. If the user enters “-1” the program will end.

Answer 41

Count <- 0 Score <- 0 WHILE score<> -1 DO OUPUT "Enter Score" INPUT score IF score > 100 THEN Count = Count+1 ELSE ENDIF ENDWHILE OUPUT Count

Question 42

What are the 4 string operations:

Answer 42

- LENGTH ( ) - LCASE ( ) - UCASE ( ) - SUBSTRING ( str, start, length)

Question 43

What does LENGTH ( ) do?

Answer 43

Output number of char in string value

Question 44

SUBSTRING (Ziqi Ding, 2, 5)

Answer 44

iqi D ,5: count 5 on from start char

Question 45

How to declare what data type something is

Answer 45

DECLARE Name: STRING DECLARE Age: CHAR

Question 46

In Pseudocode does the word number start with 0 or 1

Answer 46

1