17 replies to this topic

[toto_7]

Operation_1(A) : if ( ALPHABET[value(A)] )
return ERROR
else
ALPHABET[value(A)] = true ;

Operation_2(A) : return ALPHABET[value(A)] ;

Operation_3() : int N = 0 ;
for (int i=0; i<26; i++)
if ( ALPHABET[i] )
N++ ;
return N ;

Operation_4(A) : if ( ! ALPHABET[value(A)] )
return ERROR
else
ALPHABET[value(A)] = false ;

Operation_5() : int N = 0 ;
for (int i=0; i<26; i++)
if ( ALPHABET[i] )
return FALSE ;
return TRUE ;

I have the function value() who takes an upper-case letter and returns an integer value 0 for "A"...25 for "Z". All the letters are mapped into 26 boolean elements of a linear array ALPHABET and initialised to FALSE.

My question is what abstract data type are implemented by this operations, i think is Queue but im not 100% sure. Can any one make it clearer?

Thank you

[gregwarner]

I don't see any reference to Queue in your pseudocode. Where did you get the idea that it was Queue?

An Abstract Data Type is simply a form for describing similar data types that behave similarly or have similar symantics. (For a more thorough explanation of ADT, see Abstract data type - Wikipedia, the free encyclopedia )

In your pseudocode, what data types are mentioned that aren't primitives? (Hint: Primitives are things like int, double...)

[toto_7]

I have this exercise and i have to state what data type is implemented by these operations...(Set, Stack, Queue, Graph or Tree)

[gregwarner]

I guess I'm not understanding the question. Is the exercise asking which ADT's are implemented by the Set, Stack, Queue, Graph, and Tree?

[toto_7]

State what abstract data type is implemented by these operations

Exactly, this is the question...

[gregwarner]

I guess I'm a little confused because Set, Stack, Queue, etc... aren't technically operations, they are types. They aren't really abstract types, they're template classes. Abstract classes are more for deriving subclasses which mimic functionality of the parent abstract class. (In C++, it's done by declaring the methods with the "virtual" keyword.) Template classes are for writing a class beforehand before you know what datatypes they will operate on.

Could you post more information on the question please?

If somebody else is picking up on what this is asking, please feel free to help me out.

[toto_7]

Thats all i have for the exercise, given 5 operations and a question. By the way in my course learned that some ADTs are Set, Stack, Queue, Graph, and Tree. Is that wrong?

[gregwarner]

No, not wrong, I guess I was just confused by the wording.

As far as the question goes, I don't know how to answer because the question is asking, "what abstract data type is implemented by these operations." Strictly speaking, Set, Stack, Queue, etc., aren't operations. Operations would be things like push, pop, add, remove, etc. Operations are the things you can perform on data types such as set, stack, queue, etc.

I also don't know how to answer what abstract data type is implemented by set, stack, queue, etc., because those are the abstract data types. I don't know that any abstract data type is implemented by them.

If you could seek some clarification on the question maybe I could help you more.

Unless someone else is seeing the obvious that I'm missing?

[toto_7]

ok, i appreciate your effort until now, thank you

[WingedPanther]

What you need to do is look at each of the operations listed, and figure out whether it corresponds to push, pop, isempty, etc. For pop, does it pop the value that was pushed last, or pushed first?

[toto_7]

Still confused!!! :S If pop the last pushed is stack, if pop the first is queue. right?

[WingedPanther]

Correct.