How to develop a software in c++? i know it should be done through a program. But how can i develop it into a software which runs like the dos counter-part of eclipse or media player or any other software. I mean how can I make the program to remember the values the user assigned to its variables without erasing it every time I close the .exe file running the program? Hope you understand my question.
You should store that value outside, in example in XML, JSON, SQLITE. The keyword for today is Database.
The simple example is QT with SQLITE or even simpler reading/writing to file. Here is a basic tutorial aka reference.
Here is the usage of rapidxml (pretty fast)
How to develop a software in c++?
Well the simplest way to get into process is to track some open software applications. There is a lot of tasks marked as Junior Job. Try to implement it.
How to develop a software in c++?
I suggest picking up a good book on C++ and do all included exercises. If you don't understand a particular portion of the language or standard library refer to cppreference.com and StackOverflow. Both have search facilities.
I'm sure there are plenty of tutorials available on the web but I cannot personally recommend any for beginners.
I mean how can I make the program to remember the values the user assigned to its variables
The easiest way without using any third party libraries or OS specific API's is to use std::ifstream and std::ofstream.
Since it appears you are developing for Windows platforms (.exe mentioned) I suggest you also take a look at the registry functions available in the Windows API.
Here is a link which guides one for writing data to a file.
http://www.cplusplus.com/doc/tutorial/files/
If you want to use this data the next time you execute the program,
maybe you want to incorporate an if statement that says if the
file exists and is not empty, then import the data from there into
your program (which means adding lines to your program to also read
in the data from the file).
Related
This is kind of a beginner question, so please let me know if this is appropriate for this website and if not, where else I should be asking this.
I've just gotten into the basics of C++ (pretty much what's being taught in this video from FreeCodeCamp: https://www.youtube.com/watch?v=vLnPwxZdW4Y). Obviously, not everything there is to know is discussed in this tutorial and I've been running into a couple of things in other demonstration vids that I don't quite get yet.
For example, this quick demonstration of how Tetris can be coded: https://www.youtube.com/watch?v=zH_omFPqMO4&t=0m25s) you can see him use the command 'RenderWindow', which apparently creates a new window the size of his choice (320*480 pixels in this case). This doesn't seem to be a standard function in C++, so I assume he somehow imported it. How can I do this myself? Does it have to with the file inclusions written at the top of the file (#include <SFML/Graphics.hpp>)? If so, how can I learn more about such files, where can I find them (is it anything like the Python Package Index, or interfaces in Java) and can I create them myself? Any general explanatory words on this?
Thanks in advance.
This doesn't seem to be a standard function in C++
That is correct. There are no functions for graphics nor window handling in C++.
so I assume he somehow imported it. How can I do this myself?
Usually, you would pick a library of your choice (there are many), or do it yourself by using whatever API your operating system provides.
Does it have to with the file inclusions written at the top of the file (#include <SFML/Graphics.hpp>)?
Yes, SFML is one of those libraries.
If so, how can I learn more about such files
You would go to the library's homepage and read the documentation.
where can I find them
Try searching the web for lists of libraries, articles, projects, etc.
is it anything like the Python Package Index
No, there is no standard one for C++. There are several package managers, build systems, etc. Popular libraries are in most of them and support one or more build systems.
I have a C++ library that we're using to override some functions for testing. However, we just have it set up to prompt from the command line.
I'm looking to create a GUI for it to use as the prompt rather than command line.
I've been looking into Tcl/Tk, but I'm not quite sure if it can do what I'd like. Is it possible to use the Tcl/Tk wrapper to stylize my library functions?
Can I just include Tcl/Tk in my C++ code somehow, so that I call those functions right inside my library?
Probably easiest to wrap your C++ functions with swig and call them from Tcl, see this intro, then you can use Tk to create a GUI for your input parameters and/or displaying your results.
The two mechanisms to consider for this are SWIG and critcl in C++ mode. The former is probably easier to get going with as you already have the C++ code, and the latter produces more natural (more “Tcl-ish”) language embeddings.
Once you've got your library connected up, the first thing to do is probably to write a little test suite (using tcltest, a standard package supplied with Tcl) so that you know that things are working. (That saves a lot of heartache and hair-tearing later on!) If your code is working fine, you'll probably have a good enough test suite within a day or two. Then hook it up to your GUI (Tk is indeed good for that), which can be written safe in the knowledge that it's using a business logic layer that's working fine. I encourage you to avoid putting any GUI code in your C++ code if you can; it's far better to produce a clean interface without entanglements. (OK, it's not always possible to avoid, especially if you're doing heavy visualization, but it's a lot more work…)
Perhaps some of you people have heard of http://suckless.org/ and their set of Unix tools. Basically, they're a set of programs that each aim to do one thing but do it well, while still being as simple and resource-light as possible.
I've been trying to find a way to reproduce this style of programming on Windows with C++ but all the libraries I know of would produce binaries that are huge with respect to their function. Even the simplest of anything Qt, for example, is generally several megabytes large. I'm not against packaging dependencies along with distributables but I wouldn't want to do it to that level.
Binary size is not one of my main goals but simplicity is and big libraries like these are, by construction, not simple. If binary size were your primary concern you could use runtime compression just like kkreiger or malware.
A possibility would be to go commando and use only ISO Standard C++ libraries but rebuilding a sockets or networking system for a small single-purpose application is not really something anyone would want to be troubled with.
For some reason I thought there was some general-purpouse library that Windows developers could count on everyone and their grandma having readily accessible but now I don't know if anything like that exists. What can you use to write code that adheres to the Unix Philosophy but for Windows targets?
You should target the Win32 API directly. You can't get much lower level than that. In the Windows world, everything directly or indirectly wraps the SDK functions, including the so-called "standard C++ libraries".
Alternatively, you could use something like MFC or WTL, which are relatively thin C++ wrappers over the Win32 API. Because of the overhead of the class libraries, such programs will be slightly smaller than those created using only the SDK, but nowadays, the actual overhead is completely insignificant.
The desires expressed in your question are precisely why I learned and still use the Win32 API today, so that's definitely what I would go with. Plus, your programs will look and feel native, which is way better than the crap most "cross-platform GUI toolkits" put out. The advantages of this can't be underestimated.
But if you just open up Visual Studio and compile a simple little SDK "Hello World" app, it'll still be awfully large. Kilobytes, to be sure, but that still seems like a lot for about the simplest app imaginable. If you really need to cut things down further, you can try telling Visual Studio not to link to the C runtime libraries and define your own main entrypoint. This does mean that you'll have to implement all of your own startup initialization code, but this can reduce the size of a trivial app substantially.
Matt Pietrek had this same idea some years ago, although you'll probably want to take time to "modernize" his original code significantly if you decide to go this route.
FLTK is a popular cross platform minimal gui toolkit.
Or a popular alternative if you don't need too much detailed interaction is just to fire up a minimal embedded webserver and do all the 'gui' in html in a browser.
I know that a lot of c/c++ XML library questions have been asked already (I tried to read through all of them before getting to this).
Here are the things I'm going to need in my own project:
Excellent performance
SAX2
Validation
Open source
Cross platform
I was going to use Xerces-C, but I see that a simple SAX2 setup with nothing going on in the filter is taking 5 seconds to run. (Perhaps I'm doing something wrong here?)
I would like to use libxml++, but as I tried to get it set up on my MacBook, there were some crazy dependencies that took me all the way back to gtk-doc, at which point I sort of tabled the idea.
So now I'm at libxml2. Is this the way to go? Have I missed an important option, bearing in mind the five requirements above? I don't mind using a (good) c-library like libxml2, but a c++ interface would be nice. (I don't like Xerces-C's API very much.)
I am willing to bend on the SAX2 requirement if comparable functionality is available.
Having spent a goodly amount of time on this same problem, it was my conclusion that libxml2 is the best option available under your guidelines. The C interface is not too difficult to use and it's very fast.
There are some other good options for commercial libraries, but most of the other comparable open-source options are either painfully slow or are mired in a deep, annoying vat of dependency soup.
You say you need these things in your project, but don't give any idea of the pipeline. For example, we had a whole load of static XML files which needed to be loaded quickly, but only validated rarely. So validated using a separate process in batch (using RelaxNG as it was human writable markup ) and loaded the XML using expat. The system also used XMPP, so checked streaming input, but that didn't require validating against a schema (partly because it was streamed, and mostly because most of the possible errors were not expressible in a schema).
If you need a whole host of other facilities, you can consider Qt, which has good XML support. Be warned though, it's WAY more than an XML processing library; it's a full blown application framework with support for GUIs, networking and a whole host of other things.
Qt
You can also try Poco. It's another application framework, but not as huge as Qt (i.e. no GUI-related things etc.)
Poco
Lastly, if you don't mind a C library, you can use Expat. It's not SAX per se, but writing code using Expat is somewhat like SAX. It has C++ wrappers, but they're not officially part of the project IIRC, and may not be as well-maintained or designed. I'm not too sure though.
Expat
Hope this helps!
EDIT: I misread your original post: not too sure about the validation features of these libraries, I've never used them before.
I'm looking to add full text indexing to a Linux desktop application written in C++. I am thinking that the easiest way to do this would be to call an existing library or utility. This article reviews various open source utilities available for the Gnome and KDE desktops; metatracker, recoll and stigi are all written in C++ so they each seem reasonable. But I cannot find any notable documentation on how to use them as libraries or through an API. I could, instead, use something like Clucene or Xapian, which are generic full text indexing libraries. They seem more straightforward but if I used them, I'd have to implement my own indexing daemon, an unappealing prospect.
Also, Xesam seems to be the latest thing, does anyone have any evidence that it works?
So, does anyone have experience using any of the applications or libraries? How did you use it and what documentation was useful?
I used CLucene, which you mentioned (and also Lucene.NET), and found it to be pretty good.
There's also Strigi which AFAIK works with Xesam and is the default used in KDE.
After further looking around, I found and worked with Recol. It believe that it has the best C++ interface to a full text search engine, in this case Xapian.
It is important to realize that clucene and Xapian are both highly complex libraries designed primarily for multi-user server applications. Cutting them down to a level appropriate for a client-system is not easy. If I remember correctly, Strigi has a complex, pure C interface which isn't adapted.
Clucene also doesn't seem to be that actively maintained currently and Xapian seems to be maintained. But the thing is the existence of recol, which allows you to index particular files without the massive, massive setup that raw Xapian or clucene requires - creating your own "stemming" set is not normally desirable, etc.