Hi, hope this is allowed here. I am confused about what it means to call something an abstract data type. What does it mean when a stack is called an Abstract data type.
This is a new series I'm starting, gonna cover Stacks, Bags and Queues using linked lists and arrays then cover sorting algorithms before deciding what to do after that. I'm looking for feedback I know I probably need to flesh out a bit more but I'm not that great of a writer just yet still trying to get that part down (without doing the college style "lets bloat this paper just to reach the word count" and actually have substance.)
I hope I can be of help to someone!
https://discustd.com/Blog/01-Introduction-To-Stacks-In-Java.html
I have just finished data structures class and now know how to make linked lists, hash tables and the like
however, at some point in the class, my professor said that C++ (the language the course was taught in) has libraries for all of these ADTs which we can just important in a real world setting
so in an actual career, is being able to create these ADTs important? Or is data structure class just an exercise in learning how they work?
Watching Georgia Tech 1332 Edx videos.
The first video went over the array ADT, then brought up ArrayLists but said it implements a list ADT. I can't tell the difference between array and list abstract data types. In Python a list can have non-similar elements, but I know for sure an array cannot. I'm not sure if a list can. Judging by the name "arraylist", I'm guessing it implements a mix of both arrays and lists, further implying the two concepts are distinct, but I can't find any text that compares them.
Hello !
I am currently working on the 5th volume of the Software Foundations' texbook on "Verifiable C" in Coq which can be found here.
I am having trouble understanding how to solve:
1 subgoal
Espec : OracleKind
p : val
i : Z
il : list Z
gv : globals
Delta_specs := abbreviate : PTree.t funspec
Delta := abbreviate : tycontext
POSTCONDITION := abbreviate : ret_assert
x, y : val
MORE_COMMANDS := abbreviate : statement
______________________________________(1/1)
semax Delta
(PROP ( )
LOCAL (temp _i (Vint (Int.repr i)); temp _q x; gvars gv)
SEP (malloc_token Ews (Tstruct _stack noattr) p; data_at Ews (Tstruct _stack noattr) y p;
malloc_token Ews (Tstruct _cons noattr) x; data_at Ews (Tstruct _cons noattr) (Vint (Int.repr i), y) x;
listrep il y; mem_mgr gv)) (_free([(_q)%expr]);
MORE_COMMANDS) POSTCONDITION
My proof looks like this so far:
(** **** Exercise: 2 stars, standard (body_pop) *)
Lemma body_pop: semax_body Vprog Gprog f_pop pop_spec.
Proof.
start_function.
unfold stack in *. Intros x.
forward.
unfold listrep; fold listrep. Intros y.
forward.
forward.
deadvars.
forward. hint.
The last hint gives me this message:
When doing forward_call through this call to _free
you need to supply a WITH-witness of type (type*val*globals) and you need to supply a proof that x
<>nullval. Look in your SEP clauses for 'data_at _ (Tstruct _cons noattr) _ x ', which will be useful for both.
Regarding the proof, assert_PROP(...) will make use of the fact that data_at cannot be a nullval.
Regarding the witness, you should look at the funspec declared for _free
to see what will be needed; look in Verif_stack.v at free_spec_example.
But in particular, for the type, you can use the second argument of the data_at, that is,
(Tstruct _cons noattr) .
Regarding the 'globals', you have gv : globals above the line.
THAT WAS NOT A STANDARD VST HINT, IT IS SPECIAL FOR THE VC VOLUME OF SOFTWARE FOUNDATIONS.
STANDARD VST HINTS WOULD BE AS FOLLOWS:
Hint: try 'forward_call x', where x is a value to instantiate the tuple of the function's WITH clause. If you want more information about the _type_ of the argument that you must supply to forward_call, do 'forward' for information
I tried
... keep reading on reddit ➡What is the difference between abstract data type and concrete data type in data structures? It seems like a simple concept, but I am struggling to understand it.
An abstract data type is abstract implementation wise, meaning it can be implemented through various ways to achieves its functionality?
Is a concrete data type data structure a data type that is known to have a set design/implementation and there is really no other way to implement it?
I read online how a stack is an abstract data type. If I want to could I not implement the stack with a queue, which is another abstract data type, or could I implement the stack with a concrete data type such as an array?
Same thing with concrete data types, could I not implement an array with an abstract data type such as a stack?
Could somebody please help clear this confusion up?
I've been reading a bit about data structures and I came across abstract data types. I don't understand the function of abstract data types. I was wondering whether there was a specific ruleset which ADT must adhere to when it goes from point A to point B in a code. If possible can someone explain ADT to me in detail or link me to an intresting article to read regarding data structures and ADT.
Take for example this text on Haskell (though ADTs are not exclusive to Haskell.)
>The "algebra" here is "sums" and "products":
>
>"sum" is alternation (A | B, meaning A or B but not both)
>
>"product" is combination (A B, meaning A and B together)
Given that the traditional definition - coming from a basic math background - of a sum means to ADD two terms, it is totally confusing why in functional programming, SUM here is used to define a mutually exclusive , "or ", choice. Can anyone provide insight as to the why?
So, I am starting to learn about stacks and queues etc. but from what I understand you have to write classes for these objects. Since they are so popular, why aren't they already implemented in python? They could write these classes so much better than me and it would be so much more convenient. (I am lazy.)
Hi all,
TLDR, what components in Azure would you apply to do a monte carlo analysis on a low millions data set? Any other tips?
We are going to be analysing some loan portfolios. Probably a few millions loans. For each loan we would apply a sort of decision tree with applied probabilities. e.g. 60% renegotiated, 20% go to foreclosure, 20% go to legal process. There would then another 1 or 2 nodes, so of renegotiated, 50% go to foreclosure. NB that the rules will be actually a little bit more complicated than that in that the probabilities could be affected by other dimensions in the data.
We'd then want to run this through a monte carlo type analysis and record the results. We would likely also want to see the impact of changing the decision trees, effectively running a new monte carlo with some different inputs.
Not sure if this is more of an analytics question than business intelligence, but I've had good answers here before. Question is what is the most effective tool(s) for this kind of analysis.
Does anyone have a copy of the paper from the title? Published 1982, but it isn't on Stroustrup's website, so perhaps a stretch, but are there any copies of this paper in the wild? Presumably this paper covers "C with classes" and early preprocessing of abstract types in C. I'm extremely curious.
Hi everyone.
I prefer C to C++ for many reasons. What i miss sometime from C++ is STL. i Which libraries do you usually use for not reinventing the wheel very time ? ( I used search.h of posix, libavl and glib but i was just curious if there where popular alternatives )
I thought they were the same but all the sources I check say there’s a distinction. Yet one site listed queues and stacks as both. Plz halp thx.
Can we only have an abstract data type definition for concrete data structures? I ask because this Wikipedia link says how "This mathematical model contrasts with data structures, which are concrete representations of data, and are the point of view of an implementer, not a user." I thought we can have an ADT for anything, not just a data structure, and do a concrete implementation for it then.
Is a ADT just: int x = 5;
and why is a Linked List not a ADT?
I am struggling to understand the difference between those two concepts. To me they look pretty much the same, AlgDT allow type composition but so do AbsDT right?
For example I can compose ints and chars in an abstract data type:
struct coordinates {
int x;
int y;
char data_point_name[5];
};
One powerful feature of AlgDT that really impressed was that I was able to define the set of natural numbers recursively:
data Nat = Z | S Nat
where Z is 0 and S the successor function. That is something that I could not do using 'struct' but does it make the different between AlgDTs and AbsDTs a fundamental one?
I know that I am confusing something and that there is a flaw in my understanding but I don't know what! Thank you for reading.
Hi,
So I was just reading about Abstract Data Types,and how they can encapsulate your code, but I still haven't really quite understood what the difference would be between an ADT with all its methods, and a static variable that has methods as well used to modify it or access it. Would anyone be so kind as to shine some light on this matter?
Thank you.
So data structures are how you store data and what not. ADTs are how you implement it. Like a list is a data structure. I can treat it like a list, a queue, single linked list, etc. So how I treat is an ADT. So for Arrays, my course says lists, dynamic array. But is an array itself an ADT as well? Just like a list being an ADT and data structure? I don't need to make an ArrayList or dynamic array. I can just treat it like a singular array. Just like I can treat a list as a list rather than single linked list. Maybe I'm confused. Also, why are ArrayList methods already defined but I have to define linked list methods myself?
What is the difference between abstract data type and concrete data type in data structures? It seems like a simple concept, but I am struggling to understand it.
An abstract data type is abstract implementation wise, meaning it can be implemented through various ways to achieves its functionality?
Is a concrete data type data structure a data type that is known to have a set design/implementation and there is really no other way to implement it?
I read online how a stack is an abstract data type. If I want to could I not implement the stack with a queue, which is another abstract data type, or could I implement the stack with a concrete data type such as an array?
Same thing with concrete data types, could I not implement an array with an abstract data type such as a stack?
Could somebody please help clear this confusion up?
To me there is only one way to implement a linked list with nodes, but some places online say a linked list an abstract data type, I thought it was a concrete data type. Which one would linked list be as a data structure?
)