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Wjec Cp4 Cp5

Should get approx. 70-80% on both papers what topics is anyone else doing this board concentrating on. I think BNF, languages and algorithms for CP4 on friday.

Reply 1

jOnNy BoRrEll

Did anyone else take the CP4 test today?

Reply 2

Fields

Was anyone else pissed off about the question on CP4 that asked us to write an algorithm in either pseudocode or a high-level language? I was under the impression we would have to interpret rather than write algorithms, and that's the way it;s been on every past paper I've looked at. Of course, I could be wrong...

Reply 3

jOnNy BoRrEll

fieldsofanfield

No your right. I have a feeling that the A boundary will be low this year. One because of that algorithm (which i attempted - was never taught at college, learnt off my dad) and everyone came out of the exam saying it was hard.

I brought the paper home and with my answers that i put i got about 70-80% on it so i'm pretty chuffed.

Reply 4

Fields

Yeah, it was by far the hardest CP4 paper I've seen. I think I just managed to get that algorithm question from past programming experience, but I didn't bother revising it beforehand because I didn't think I had to. Still, I'm fairly confident about computing because I got good marks on last year's modules and my coursework was good.

Reply 5

chuckD

for once i actually thought this exam wasnt too bad...the algorithm was ok for me cz i do alot of programming. Still think i get didnt the 4 marks for it tho. Managed to make this the first exam ive ever fallen asleep in! Possibly not a good idea but they wouldnt let us leave after we'd finished and checked.

Reply 6

MdSalih

I thought it (CP4) was a pretty good paper - Here's the Post Mortem:

[2]1)i) Example of data to store in record about the staff. Why use a record?
Store their Name, Age, Gender, NI etc.
Use a record because you can store data of different types.

[2]1)ii)Example of 3D array.
Draw a table with cells split in two showing two different pieces of information for a given slot

[3]2)a)i) 3 Benefits of a GUI over text based
- Not much IT skill needed to use the system
- Can use the system and become familiar with a system which doesn't something else that uses a similar interface
- It is user friendly.

[2]2)a)ii) 2 benefits of text based system over GUI

- Versatlie - switches and stuff
- Quicker to do things as opposed to going through loads of menus.

[1]2)b)i) Why is handwriting recogition useful

Something like its more practical in a particular environment

[1]2)b)ii) Drawback of Hand Writing Recognition

User may need training to use the system

[1]2)c)i) Form Dialogue - what is it ?

On-Screen form utilising drop down boxes, checkboxes etc.

[1]2)c)ii) Natural Language Interface

Standard English can be input into a special form to perform an operation - i.e. some internet search engines

[1]2)d)i) How would you evaluate the HCI?

See if it meets the specification requirments - i.e. is it suitable for the environment it will be used in and the user who will be using it?

[1]3)i) Explain Overflow

Number which is too big to be stored in the allocated memory - this can arise as a result of an arithmetical calculation

[1]3)ii) Explain Underflow

Again, can be a result of an arithmetical calculation - it occurs when the number to be stored is too small to be represented.
4)a)

[1]4)a)i) Name the type of structure displayed

A Binary Tree

[1]4)a)ii) What is the value of the root node

2617

[1]4)a)iii) the root in locating the number 2528

2617,2456,2537,2528

[1]4)a)iv) Add 3106 to the tree.

[1]4)a)v) What would happen when we tried to look for 2550?

Would return that the search yielded no results.

[4]4)a)b) Two other data structures with diagrams

Draw a Stack & Queue with the relevant pointers

[1]5)a)i) -7 in binary using two's compliment

+ 7: 00000111
invert: 11111000
Add 1: 11111001

[2]5)a)ii) Show -7 + 20 = 13 in binary

11111001
00010100
00001101

(1x1) + (1x4) + (1*8) = 13

[2]5)b) Explain Sign/Magnitude with illustration

One bit is used to represent whether the number is +ve (0) or -ve (1). Remaining bits used to show the magnitude

00000001
^^^^^^^ The Magnitude
^ The Sign

[1]5)c) 1 = 00110001 2 = 00110010 ... how would you show 5 ?
00110001 - 1
00110010 - 2
00110011 - 3
00110100 - 4
00110101 - 5 <<<

[2]6)a) Two ways to portray an algorithm
- Pseudo Code
- Structured English

[1]6)b)i) Feature of a recursive algorithm other than calling to itself.

A Termination Condition

[1]6)b)ii) An advantage of recursion

Efficiency.

[2]6)c)i) Passing a parameter using reference & Benefits

Using a variable to input the parameter - and value can be used in that single declaration (not sure about this one... blagged it...)

[2]6)c)ii) Passing a parameter using value & Benefits

Using an exact value to input the parameter - Exact value means that no other value can be input as a result of another function overwriting a different value for a variable (also not sure about this one... )

7)a) J: 10011010 K: 00111000
[1]7)a)i) NOT J

01100101

[1]7)a)ii) J XOR K

10100010

7)b) M: 10000000
[1]7)b)i) Logical operation of MASK

AND

[1]7)b)ii) What effect would a MASK with M have on a 8 bit binary number
Check if its >= 128 ? (Not sure if it was this or something to do with significant numbers)

[1]8)a) What does an interpreter do?

Converts the source code to object code line by line

[2]8)b) What is Lexical Analysis, make a reference to symbol table in your explanation

Lexical analysis removes spaces, superfluous charachters and comments. All variables, identifiers, constants etc are changed into tokens and these are then tabulated in a symbol table.

[2]8)c) Explain the function of a Linking Loader with example.

Linking loader enables you to include previously compiled code into your program and makes the necessary links. An example would be when you want to include a standard module in your program - as it has already been compiled you would need to use a linking loader.

9)a)

[1]9)a)i) Name for the above diagram

Syntax Diagram

[1]9)a)i) Example of a valid 4 charachter variable name.

TSK9

[1]9)b)i) Why use BNF?

Precise/Accurate - no ambiguity

[4]9)b)ii) Example of BNF which would be used to define a Word which
- starts with a letter
- has letter in it
- can include - and '

<char>		::= A|B|C...|z
<chars>		::= <char>|<char><chars>
<symbol>	::= '|-
<symbols> 	::= <symbol>|<symbol><symbols>
<word> 		::= <chars>|<chars><symbols>|<chars><symbols><word>

[4]10) Write an algorithm to search for a value in an array of Values[1...n]


count := 1
total := n

do
	if(Values[count] == search_element)
		output count
		return
	else
		count++
while count < n+1

output 0

[8+3]11) Explain the following languages
- Procedural
- Non Procedural
- visual
- forth generation

also explain
- CASE
- Debugging Tool

Too long to be bothered with typing this up.

Reply 7

chuckD

"[1]7)b)ii) What effect would a MASK with M have on a 8 bit binary number
Check if its >= 128 ? (Not sure if it was this or something to do with significant numbers)"

i think it checks the most significant bit to see if its 1 or 0. possibly a sign check in many systems

Reply 8

Benneh

7bii was a check for whether the msb was set.

Passing by reference is when you are given the address of the variable. Any changes made to the variable in the procedure are made to the variable in main. Passing by value is when you are given a copy of the variable. Any changes made are local to the procedure and aren't reflected in main.

Adv/Dis of passing by reference: Faster(as no copy)/Can't be sure what a procedure is going to do with a variable, easily munged.
Adv/Dis of passing by value: Can ensure integrity of variable in main/Copying the variable can be slow.

I think you made the BNF overly complex and missed the bit about all letters being lowercase.


<word> ::= <letter>|<word><letter>|<word><char>
<char> ::= '|-
<letter> ::= a|b|....|y|z

I think I've messed the first two questions up though. My 3d array was just described, I missed the bit about giving example data. My head just went blank when it came to GUI's vs Text Based.

Heres to hoping CP5 will be nicer tomorrow

Reply 9

MdSalih

Benneh

I think you made the BNF overly complex and missed the bit about all letters being lowercase.


<word> ::= <letter>|<word><letter>|<word><char>
<char> ::= '|-
<letter> ::= a|b|....|y|z

The ' or - was said to be part of the word, thus it can have letters after the char - I considered this and made the BNF to accept this as well as having multiple ' and - in the word. And yep, your right - it was in lowercase.

---------------------------

How did people find the CP5 exam today? Personally found it to be a very good paper. Spent most of the time doodling on other paper.

MdSalih

Reply 10

CrazyChemist

Code:

<word> ::= <letter>|<word><letter>|<word><char>
<char> ::= '|-
<letter> ::= a|b|....|y|z

You need to have "<word> ::= <letter><word>" there somewhere i think...Just noticed that mine in the exam was far too comlpicated. Will that drop me marks u lot think? should do...

Also, anyone done CP5 today? average paper i thought - mostly standard questions with lots of writing. How do you get the two marks for the foreign key question?

Reply 11

Benneh

Cp5 was good, just forgot to answer the question on 1NF. I'll agree with lots of writing. I spent the first hour on the first 4 questions, they kept saying in detail but only awarding 2 marks so I just wrote more than I think I needed to.

Nothing else needs to be added to the BNF as the only way to start is with <letter> condition at the start. All other conditions in the <word> def require part of the word already.

You shouldn't lose marks for making it overly complicated as long as it still does the job

Reply 12

MdSalih

The foreign field question asked you to state what a foreign field was and how they are used in a relational database (or something to that effect).

So one mark for stating what a foreign field was (a field which is a key field in another table).

The second mark for saying that they're used to link tables by the key/unique field in a relation database I believe.

As for the BNF, I was under the impression that you would get the marks if it your BNF definition did what they wanted it to do - shouldn't be such a thing as too complicated :confused:

- if it doesn't do what they want it to do, then you begin to lose marks.

MdSalih

Reply 13

Fields

Well I thought CP5 was easy, nothing that I couldn't answer. Lots of writing though :mad:

Reply 14

jOnNy BoRrEll

fieldsofanfield

Well I thought CP5 was easy, nothing that I couldn't answer. Lots of writing though :mad:

I agree, wouldn't say it was easy (don't want to be jinxing myself :redface:

)
I probably got ~80% on it. Was easier than CP4 as it seemed a regurgitation of the notes. Like you said there wasn't anything which stumped me or made me think hard and i couldn't answer. Normalisation seemed ok even though it was the first year without a table. Got the paper with me, going to mark later tonight. :smile:

Does anybody know what they got in cp6 (coursework) - I was told that I got 56/63 pending any examiner adjustment - but my teacher told me that the school has never been marked down on its mark allocation.

Reply 15

MdSalih

Unmoderated was 62/63. Only find out moderated mark on results day I believe.

MdSalih

Reply 16

Fields

I can't remember what exactly I got on my coursework...59 I think.

Reply 17

CrazyChemist

congrats on the coursework then - i really didn't bother much with it and got 50 unmoderated (rubbish i know, but all i have to do is get just above 80% in the exams for an A - I reckon I can do that).

Reply 18

bilb

I was 8 UMS off an A last year, got 51 on the coursework....oh and I'm quite sure the coursework mark isn't 'moderated' unless your school/college badly marked them, though there is UMS adjustment as always. Me thinks I did reasonably well...especially after reading this thread...though why I had to forget that the damn thing was a syntax diagram is beyond me :smile:

Reply 19

CrazyChemist

bilb

Well as i understand it, the school sends a few courseworks (all of them if there are only a few in the class) off to the moderators to make sure that everyone is being marked to the same standard. Mind you most of the time nothing is changed, especially if you have experienced teachers marking.