Algorithm design and problem solving (paper2)

Question 1

What are the 4 stages of the program development life cycle?

Answer 1

-Analysis
-Design
-Coding
-Testing

Question 2

What is the analysis stage?

Answer 2

Abstraction, decomposition of the problem, identification of the problem and the requirements

Question 3

What is the design stage?

Answer 3

Decomposition, structure diagrams, flowcharts, pseudocode

Question 4

What is the coding stage?

Answer 4

Writing the program code and iterative testing

Question 5

What is the testing stage?

Answer 5

Testing the program code with the use of test data

Question 6

What is abstraction?

Answer 6

Abstraction involves identifying the key parts of the problem and removing any unnecessary detail so it becomes easier to solve

Question 7

What is decomposition?

Answer 7

Decomposition means breaking down a complex problem into smaller, manageable parts which are easier to solve

Question 8

What are the 3 types of error?

Answer 8

-Syntax error
-Logic error
-Runtime error

Question 9

What is a syntax error?

Answer 9

An error caused by a spelling or grammar mistake

Question 10

What is a logic error?

Answer 10

An error where the program still runs but the output may be incorrect for example a > symbol rather than a < symbol

Question 11

What is a runtime error?

Answer 11

An error that is detected whilst the program is still running. A division by zero will cause a runtime error

Question 12

What are the steps involved in decomposition?

Answer 12

-Identifying the main problem

-Identifying the component parts of inputs, processes outputs and storage

-List the main sub-problems, sub-systems, functions or tasks

-Break these down into similar smaller sub-problems or sub-tasks which can then be completed separately

Question 13

What can be used to show the structure of a problem in the program development life cycle?

Answer 13

Structure diagrams

Question 14

What symbol represents a flow line in a flowchart? (Draw it)

Answer 14

An arrow

Question 15

What symbol represents a decision in a flowchart? (Draw it)

Answer 15

Diamond

Question 16

What symbol represents an input/output in a flowchart? (Draw it)

Answer 16

Paralleogram

Question 17

What symbol represents a subroutine in a flowchart? (Draw it)

Answer 17

Square with 2 lines

Question 18

What symbol represents a process in a flowchart? (Draw it)

Answer 18

Square

Question 19

What symbol represents a terminator in a flowchart? (Draw it)

Answer 19

Square with rounded sides

Question 20

How does a linear search work?

Answer 20

Each item will be checked one by one in the list until the item is found - if the item isn’t there then the list will be searched without success

Question 21

Write pseudocode for a linear search

Question 22

How does a bubble sort work?

Answer 22

A bubble sort works by repeatedly going through the list to be sorted, swapping adjacent elements if they are in the wrong order

Question 23

Write pseudocode for a bubble sort

Question 24

What are the types of validation checks?

Answer 24

-Range check
-Length check
-Type check
-Presence check
-Format check
-Check digit check

Question 25

What is a range check?

Answer 25

Data must lie within a given range

Question 26

What is a length check?

Answer 26

A string input must be greater than or equal to a minimum length

Question 27

What is a type check?

Answer 27

Data must be of the correct data type

Question 28

What is a presence check?

Answer 28

A string must not be empty

Question 29

What is a format check?

Answer 29

A postcode must conform to one of a number of set formats

Question 30

What is a check digit check?

Answer 30

-A check digit is an additional digit at the end of a product code

-It is designed to check that a valid product code has been entered

Question 31

What is a double entry verification?

Answer 31

-The input of data twice

-The 2 entries are compared and if they match the entry is accepted as valid

-Setting a password uses this verification

Question 32

What are the types of test data?

Answer 32

-Normal (typical) data
-Extreme data
-Boundary data
-Abnormal or erroneous data

Question 33

What is normal data?

Answer 33

Using examples of typical data that the program is designed to handle

Question 34

What is extreme data?

Answer 34

Largest and smallest acceptable value

Question 35

What is boundary data?

Answer 35

Includes both ends of the allowed range as well as invalid data that should not be allowed, just outside the range

E.G if the range is 0-50 then the boundary data would be -1, 0, 50, 51

Question 36

What is abnormal/erroneous data?

Answer 36

Data of the wrong type

E.G. Non numerical characters is a numeric field