T8 - MS

Question 1

Describe the purpose of a truth table.

Answer 1

To show all possible inputs
…and the associated/dependent output

Question 2

Give two ways that the maintainability of this program could be improved.

Answer 2

Add comments
Name variables sensibly
Put into subroutine / procedure /
function
Use loop / iteration

Question 3

two examples of defensive design

Answer 3

Input sanitisation

Validation

Verification

Authentication

Maintainable code

Question 4

Defensive design - input sanitisation

Answer 4

Input sanitisation
…cleaning up input data / removing
unwanted data

Question 5

Defensive design - validation

Answer 5

Validation
…checking whether input data should
be allowed / is sensible / follows criteria

Question 6

Defensive design - verification

Answer 6

Verification
… checking whether data has been
entered correctly
…by example (e.g. double entry /
visual check)

Question 7

Defensive design - authentication

Answer 7

Authentication
…ensuring only allowed / authorised
users can gain access
…by example (e.g. usernames
/passwords)

Question 8

Defensive design - maintainable code

Answer 8

Maintainable code
…to allow other programmers to
understand the code
…by example(e.g. comments,
indentation, meaningful variable
names)

Question 9

Explain the purpose of testing a program

Answer 9

Check the program meets the user
requirements
Check the program works
check the program doesn’t crash

Question 10

Describe the difference between iterative testing and final testing.

Answer 10

Iterative is during development //
repeatedly testing after/while making
changes
Final is when the development is
(almost) complete

Question 11

Define the term casting

Answer 11

Convert/change one data type to another

Question 12

Describe two methods of translating high level code into machine code.

Answer 12

Compiler
…translates code in one go / all at
once
…produces an executable file // does
not need to be compiled again
Interpreter
…translates code line by line.
…will be interpreted / translated every
time it is run.

Question 13

Describe the advantages of writing a program in a high-level language instead of in assembly language.

Answer 13

Easier/quicker for humans to write
Easier/quicker to read / understand /
remember
Easier/quicker to maintain / debug /
spot errors
…because code is closer to English /
uses English words