I'm seeking search tree software for a hobby project. It needs to support variable-length keys and data and several million items. It does not need to support deletions so long as the entire tree can be discarded in order to start a new one. The tree should be balanced.
It would be best if I did not need to use autotools to use it, so that I don't have to learn how to do development in such an environment, at least not yet.
It's quite late answer, but try to use code from projects:
http://www.codeproject.com/Articles/334773/Graphical-BinaryTrees
http://sourceforge.net/projects/binarytreeanim/
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According to "Head First Object-Oriented Analysis and Design", Complex projects involves first finding a feature list -> drawing use case diagrams -> breaking into smaller modules before implementing object oriented design (requirements gathering -> use cases -> OO -> design patterns etc.)
I want to understand, what is the criteria for the size of project when feature lists and use case diagrams should be implemented before finding requirements and writing use cases?
I am particularly interested in how can this knowledge be applied to my real wold problems
Example, I am working on a UI that send instrument commands to the server and displays the response back from the server. I know from customer feedback that the UI should have the following things:
It should be able to let the user select an instrument from available list and send any custom command and display the result
It should be able to let the user select an instrument and a command from available list and display the result (create commands using drag and drops from given lists)
It should be able to have capability of creating macros
Is this UI project small enough to not have steps for gathering features and drawing use case diagrams? Do we go straight to categorizing the asks as requirements and start gathering requirements and writing use cases?
How would one go about breaking down project of this nature to deduce it to its appropriate class diagrams?
I have tried considering the above mentioned asks as features and then tried creating requirements, mainly on the different states that one could have during the life cycle of the UI application but I am still not sure and unable to comprehend the teachings of the books on this project.
I haven't read the book, so I'm not sure what the author(s) of the book really wanted to emphasize here. But I assume that you misinterpreted it.
Without knowing the requirements there is no feature list. If you don't know what is needed then you can't say anything about the system's capabilities.
Gathering requirements is an iterative process. First you gather the high-level requirements in order to be able to start building a mental model about the system. This can help you to start think about the supported features. By sharing your mental model and the exposed feature set of the system with the stakeholder, it initiates the next iteration.
Here you can start talking about actors, user journeys, use cases, etc. These are mainly focusing on the happy paths. As you have more and more iterations you will reach a point where you can start talking about edge and corner cases: What suboptimal cases can we foreseen? What can we do (prevention, detection, mitigation)? How does it affect the system/actors/journeys?...
The better you understand the needs and circumstances, the better the design and implementation of the system could be.
UPDATE #1
Will we always have high-level and low-level (edge cases and detailed use cases) requirements i.e. we will first need to make use case diagrams and then write individual detailed use cases?
There are a lot of factors which can influence this. Just to name a few:
Is it a system, submodule, or component design?
Is it a green or a brownfield project?
Is the stakeholder experienced enough to know which information matters and which doesn't from the IT project perspecitive?
Does the architect / system designer have previous experience with the same domain?
Does wireframe or mockup exist at project kick-off?
Should the project satisfy special security, legal or governmental regulations?
etc...
In short, yes there can be circumstances where you don't need several iterations, but based on my experiences that's quite rare.
I'm currently working on making a recommendation system. I have all the information about what kind of books the user views. How do I build a recommendation system using that information?
The Question seems very general to me. If you're using python I would suggest you to check out the following link:
https://realpython.com/build-recommendation-engine-collaborative-filtering/
Recommendations can be created using 'collaborative filtering' where you determine similarities of users or items.
The source uses scikit-surprise which is a ready to use implementation with all code needed for a recomendation system.
The surprise library is good if you have (explicit) book ratings whereas another library called 'implicit' is better for implicit ratings within the data e.g. if the user viewed or liked something.
https://surprise.readthedocs.io/en/stable/index.html
https://benfred.github.io/implicit/index.html
It really depends on your usecase, both libraries have implemented various algorithms for your task, so you need to find the solution that fits best.
There are also lots of other libraries and implementations blogs and more on the internet but that's what I would start with.
Is there something similar to a standard library for modern ABAP (maybe even OO-Abap)? For example a curated list of objects that address some of the most common programming tasks like
high-level data structures (not just plain internal tables)
working with file paths and directories
working with files (reading, saving, ...)
working with different file types (text, csv, xml, ...)
regular expressions
working with the environment (client, application server)
...
My current workflow is to stumble upon a problem like getting the extension of a file from a filename (or something fairly similar and easy). Then I have three options:
Dig through a ton of (mostly old and lacking) posts on SDN until i maybe find a pointer to solve the problem
Hack away and create a one-off solution to the problem
Take my time and implement a good and well documented solution
Many times I feel a bit lost. A lot of the available information is old, bad or both. Is there a more structured approach to tackle the problem of finding a suitable abstraction in the ABAP-world?
To answer your first question no, unlike C, C#, Java, there is no need to include a library since all the functions are always available to you, so in that regards it might be simpler. What you are asking though is a great question, I am sure you probably see tons of queries in SDN for "Is there a Function module for?" etc.
There isn't an easy answer but In SAP ABAP I think the easiest way might be to find this is by looking at packages. Similar to a library by looking at a package for the type of function your looking for might get you there. For example if I am looking for handling files I might look for the control framework package and there I can see all the available functions/classes/methods/BAPIs etc. that are related to front end controls/file handling etc. and might be able to find what I am looking for. Note its not perfect as the way packages are used has changed from time to time so its actually better for finding functions related to for example purchasing or sales etc. but its one way that we use.
Like other languages in that we still need to know what library to link in to get the function you need, in ABAP you just have to find the related package. Hope it helps a little, I know its not perfect. Example package for front end controls
For working with the environment:
If you have access to SAP there is a transaction code called BAPI
Here you could find a hierarchical list of all the main objects in SAP (i.e. Material, Purchase Order, etc)
In this list you could find documentation, the function modules used for the object (i.e. créate/get detail/update etc)
And digging into the function modules could take a look to the structures, receiving parameters, etc
The other questions are a little bit complex, I am not aware of any comprehensive list but digging into SCN usually is easy to find a solution for the most common things like handling files, etc
In the particular case of regular expressions, SAP native language, ABAP, has keywords for handling them, but you also have a class in SAP called CL_JAVA_SCRIPT which you could use for doing thigs in "JavaScript way"
For example I used this class in the past to evaluate a simple formula provided in a string (i.e 3 + 2 * 5 )
This is an operation really complex to do in ABAP but easy to do in JS.
Hope it helps
SAP Reuse Library (SE83) is the most close thing to what you are looking for. It provides common development tasks grouped in hierarchy (UI controls, standard dialogs, confirmation prompts) and contains code snippets for each with commonly used classes/modules:
Though, it is incomplete and lacks many popular things.
Consider also DWDM, BIBS, LIBS transactions and other packages in this link.
I am a composer by profession and my computer science skills are limited though I program quite a bit of the software that I use.
What are the most reasonable ways to approach SQLite integration as a file format and database in an iOS app (it also needs to run on windows, but that is a secondary concern)?
I have been researching Hiberlite, which looks fantastic, but it seems to be little used and apparently it doesn't run well on embedded systems (iOS?) and chokes up when thousands of objects are in play. I haven't been able to get a sense of how severe those bottle necks are when running under those conditions.
The settings of thousands of objects (~50,000 though that number could expand) would be read every 1-10 seconds and written periodically. Read performance is more critical as write operations can stutter with out effecting the core operation of the app.
Given those conditions, how should I approach SQLite? My understanding is that without something like Hiberlite the entire database (many millions of entries) must be read and rewritten for every entry, is that less efficient. If that is the best approach is there a good resource to follow for implementing it?
Any advice would be greatly appreciated. My current software that I rely on is beyond buggy and needs refactoring, but due to my inexperience I am having a difficult time finding information about a reasonable approach.
I'm guessing you've probably found a solution for this by now, but I've been interested myself in embedding SQLite on Android and IOS, and I came across many C++-based ORM solutions.
Hiberlite looked possibly not fully mature (I didn't readily see a method of returning subsets of data, which is fairly standard). A framework which did draw my attention was the POCO:Data ORM library. It's based on the stream-based mechanism used in SOCI ORM. The POCO library is modular and optimised for embedded environments (I believe it also has a minimal external dependencies). Wikipedia has an article here, they outline some of its users, of which OpenFrameworks is one.
The WT ORM also looked pretty interesting.
I'm listing some of the other C++ ORM frameworks I found here, in no particular order:
http://soci.sourceforge.net
webtoolkit WT DBO ORM
http://debea.net
http://www.qxorm.com
http://sourceforge.net/apps/trac/litesql
http://otl.sourceforge.net
http://cppcms.com/sql/cppdb
http://dtemplatelib.sourceforge.net
http://code.google.com/p/qdjango
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I'm responsible of finding a good way to document the software project I'm working on.
What things are important to document? Should documentation of code and design mainly be in the code in the form of comments? Should we put text files or Word documents directly in the source control togetether with code? Should we use a wiki?
Factors to think about include how easy it is for the current team to create the documentation, and how easy it is for other developers to find, correct and extend the documentation later. My experience from many projects is that developers tend to not write documentation because the system for writing it is too complex or developer unfriendly, and that after a few years, new developers can hardly find the little documentation that was written.
I'm interested in what approaches you have used in similar projects. What worked well, what did not work well, and why?
Some key facts about the project:
The platform is C# and .NET.
We use Visual Studio and Team Foundation Server for source control and work item (task) management.
We use Scrum and test-driven development and are inspired by domain-driven design.
The software consists of a collection of web services and two GUI clients.
Other clients are going to integrate with the web services in the future. The integration will be done by other developers on other teams (so the web services form a kind of API).
SharePoint is heavily used throughout the development environment. Most projects have a SharePoint site, including ours.
On our project's SharePoint site we currently have a bunch of MS Office documents on things like requirements, design, presentations for stakeholders etc. Keeping everything up to date is hard.
We also have a SharePoint wiki for the development team only, where we document things in an unstructured manner as we go along. Examples include how our build scripts are organized, our testing policy, coding guidelines.
The software is an in-house application in a fairly big financial institution.
The software is developed by a team of six people over a period of ~1 year.
The developers are consultants hired in for this project only, and will not be available to help in the future (unless the client decides to pay for it).
The client has few guidlines for how this kind of project should be documented.
I think the most important things to document are the decisions. This goes for everything from requirements to architectural choices. What are the requirements of module X? How are these requirements represented in the architecture? Why did you choose architectural pattern A over B? What are the benefits? The same goes for source code: it is common knowledge that commenting the why is way better than the how.
How you document these decisions does not matter that much in my opinion, whether you use a Wiki or a Requirements document made in Word. More important is that these documents are always up-to-date and that it is easy for anyone to access them. This can be achieved by using a wiki, or placing the documents under source control, as you say. If only a few have access to them, they are more likely not to get updated, and not to be read when necessary.
We use a Wiki for our current project and it works very well. It is easy to access for anyone (developers, managers, and customers) and a history can track changes, so you know what has been changed and why. Furthermore, we try to document the code in a meaningful way and document the major design decisions. We try not to document too much, e.g. minor things, as it is always hard to keep those things up-to-date and it is not worth the effort, imho.
Worst for me than lack of documentation is excess of documentation.
Keep in mind that yes: it's really important to document your project, but also that the major part of your documentation is always at risk of never been read at all.
So, I think that a good starting point consist in thinking of your documentation more like something that you may use to introduce new developers to your project than an over detailed description of the inner workings of your software.
G'day,
Definitely use a wiki. I'd recommend TWiki as it's an excellent and extensive implementation of a wiki without being too complicated to install and manage.
Here's a couple of initial thoughts.
Categories:
Start off with an initial ontology of what you want to capture but
allow people to add new categories or sub-categories as required,
allow people to retitle (sub-)categories as required and maybe as agreed for this one so you don't get fragmentation for multiple names for basically the same thing.
let any initial (sub-)categories wither and die if they are left empty. Do this at the end of the project as some areas may only have entries towards the end of a project.
Tagging:
Start using a tag cloud. BTW here's an excellent plug-in available for TWiki to start classifying content early on in the project. Retrofitting tags is almost impossible to do. Starting tagging early also allows people to search for information that may be there already rather than having the same info located in multiple places.
HTH I'll come back and add more points as I think of them.
First and most important, have the comments written in such a way that NDoc can parse them. This is the best way to have the code itself documented, as the developers have to change their development practices very little, and you can generate pages that explain the code without having to look at the code.
Second, getting developers to write documentation is not easy, and getting them to do it might be an exercise in futility. This is where products like Fogbugz come into play. They will help manage the development with tickets, help track check ins, and when your done an iteration, generate release notes.
In conclusion, your best bet is to find the most effective solution that fits in with the devs existing process. If it impacts their development process very little, they will be more likely to adopt the system.