OCR A-level Computer Science Paper 2 (H446/02) - 19th June 2023 [Exam Chat]

Hopefully not OOP :s-smilie:

Original post by anonymoususerUK

Thanks for making this thread.

Any ideas on what will come up? :smile:

Reply 3

joylinjoseph

2

Original post by swnap

Hopefully not OOP :s-smilie:

OOP is actually the worst. I hate it soo much😭😭

Reply 4

swnap

I literally dont have a clue how to do it 😭My CS teachers are shocking, I've practically self taught myself the spec 😂

Original post by joylinjoseph

OOP is actually the worst. I hate it soo much😭😭

Reply 5

joylinjoseph

2

Original post by swnap

I literally dont have a clue how to do it 😭My CS teachers are shocking, I've practically self taught myself the spec 😂

😭😭same with me tbf, I just tend to write the first line and then end last line…always manage to get a mark. But if anyone knows how to answer it properly pls lmk😂💀

Reply 6

meowtrees

5

Feeling sad about computer science. Anyone else have any tips on how to get good on binary stuff? The craig and dave video's are so boring.

Reply 7

swnap

Original post by meowtrees

Feeling sad about computer science. Anyone else have any tips on how to get good on binary stuff? The craig and dave video's are so boring.

WWhat sort of binary stuff?

Reply 8

Original post by meowtrees

Feeling sad about computer science. Anyone else have any tips on how to get good on binary stuff? The craig and dave video's are so boring.

isaac computerscience wesbite is helpful imo

Reply 9

does anyone know what the best/easiest quick sort method would be to learn for the exam in terms knowing how describe the steps and/or applying it to a data set, cause everywhere i look it’s something different or more complex😐

Reply 10

ItsMe9798

8

Original post by joylinjoseph

😭😭same with me tbf, I just tend to write the first line and then end last line…always manage to get a mark. But if anyone knows how to answer it properly pls lmk😂💀

For OOP, as long as you know the basics, you should be able to get at least something. I've been struggling on it for a while, but I have got so far...

Definitions:
- Class: a template to create an object, outlining the states and behaviours.
- Object: an instance of a class, with assigned states and behaviours.
- Attribute: the states of an object.
- Methods: the behaviours of an object.
- Instantiation: creating an object from a class.
- Encapsulation: making attributes private, so they cannot be directly accessed or modified without a given public method.
- Inheritance: creating a class template from another class, of which includes the same methods and attributes, but may have additional of its own (the subclass takes priority and overwrites the superclass).
- Polymorphism: methods that produce different outcomes, depending on the class it is used on, or how it is used.

Basic Code:
class className
private attribute1
private attribute2

public procedure new(givenAttribute1,givenAttribute2)
attribute1 = givenAttribute1
attribute2 = givenAttribute2
endprocedure

public function set_attribute()
attribute1 = newValue
endfunction
endclass

Create an object code:
newObject = new className ("attribute1 value", "attribute 2 value")

Reply 11

sdosf

7

Original post by hhhhheeeee

does anyone know what the best/easiest quick sort method would be to learn for the exam in terms knowing how describe the steps and/or applying it to a data set, cause everywhere i look it’s something different or more complex😐

so apparently there are two methods, though both are accepted by OCR.
One being 'divide and conquer' (the list is split down) and the other involving two pointers that increment. Honestly I'm not sure about the latter as it is really confusing.
I find divide and conquer to be the simplest.

We need to sort these 7 numbers:
4 3 7 2 5 1 6
First we choose a pointer - we have to be consistent with how we do it. I would just choose the leftmost number. but you could do rightmost or central etc.
4 3 7 2 5 1 6
We then want to move every number smaller than 4 to the left, and leave everything larger to the right:
(you also need to be consistent in how you are sliding the numbers along)
3 2 1 4 7 5 6
4 is in the correct place. We now have two sublists with one number in the correct place inbetween, [3 2 1] 4 [7 5 6]
So we perform quicksort on thee two lists. Lets start with 3 2 1:
3 2 1 (we choose 3 as it is the leftmost number - same as we did above)
2 1 3
Now, as both 3 and 4 are in the correct places, the full list looks like
[2 1] 3 4 [7 5 6]
So we keep going:
2 1
1 2 - this is sorted as there is no need to sort a list with one item ([1]), leaving us with 1 2 3 4 [7 5 6]
Now we sort the 'other half':
7 5 6
[5 6] 7:
5 6 doesn't change as 6 > 5:
5 6
So the completed 'other half' looks like 5 6 7
Combining with the rest of the list:
1 2 3 4 5 6 7

Let me know if that is at all helpful to you. If something is still not making sense pls lmk! :smile:

Reply 12

Original post by sdosf

so apparently there are two methods, though both are accepted by OCR.
One being 'divide and conquer' (the list is split down) and the other involving two pointers that increment. Honestly I'm not sure about the latter as it is really confusing.
I find divide and conquer to be the simplest.

We need to sort these 7 numbers:
4 3 7 2 5 1 6
First we choose a pointer - we have to be consistent with how we do it. I would just choose the leftmost number. but you could do rightmost or central etc.
4 3 7 2 5 1 6
We then want to move every number smaller than 4 to the left, and leave everything larger to the right:
(you also need to be consistent in how you are sliding the numbers along)
3 2 1 4 7 5 6
4 is in the correct place. We now have two sublists with one number in the correct place inbetween, [3 2 1] 4 [7 5 6]
So we perform quicksort on thee two lists. Lets start with 3 2 1:
3 2 1 (we choose 3 as it is the leftmost number - same as we did above)
2 1 3
Now, as both 3 and 4 are in the correct places, the full list looks like
[2 1] 3 4 [7 5 6]
So we keep going:
2 1
1 2 - this is sorted as there is no need to sort a list with one item ([1]), leaving us with 1 2 3 4 [7 5 6]
Now we sort the 'other half':
7 5 6
[5 6] 7:
5 6 doesn't change as 6 > 5:
5 6
So the completed 'other half' looks like 5 6 7
Combining with the rest of the list:
1 2 3 4 5 6 7

Let me know if that is at all helpful to you. If something is still not making sense pls lmk! :smile:

ahhh thank you so much ((: that makes perfect sense this one seems much simpler then the one i was attempting to learn

just wondering do you by any chance know where to find the pseudocode for the divide and conquer quick sort cause i was told writing the code from scratch/a gap fill has a possibility of coming up in the exam¿ if not thank you anyway🤞

Reply 13

Mr_Yoshi

Original post by hhhhheeeee

ahhh thank you so much ((: that makes perfect sense this one seems much simpler then the one i was attempting to learn

just wondering do you by any chance know where to find the pseudocode for the divide and conquer quick sort cause i was told writing the code from scratch/a gap fill has a possibility of coming up in the exam¿ if not thank you anyway🤞

there's no way we have to code it on our own. For filling in gaps, this could come up, I prefer to know the idea of the method and then think really hard about the conditions for if statements when filling in since there's enough time to try to trace it

Reply 14

rhys_kenn

Do you guys think that OOP is likely to come up on this paper as it didnt come up on paper 1 which i thought was quite strange. Idk i have a feeling theres gonna be a lot of pseudocode on this paper tbh.

Reply 15

Mr_Yoshi

Original post by rhys_kenn

Do you guys think that OOP is likely to come up on this paper as it didnt come up on paper 1 which i thought was quite strange. Idk i have a feeling theres gonna be a lot of pseudocode on this paper tbh.

lots of code lots of oop

Reply 16

rhys_kenn

Original post by Mr_Yoshi

lots of code lots of oop

I hope so i put in a lot of practice for OOP before the last paper lol.

Reply 17