3

Paraphrasing a recent question: https://softwareengineering.stackexchange.com/questions/52608/what-is-object-oriented-programming-ill-suited-for

I would like to ask the opposite question:

What kind of programs cannot be written unless you use OOP?
What kind of programs are not recommended to be written using non-OOP techniques?
What kind of programs need OOP in order to even be written? What kind of programs would be too hard to write without OOP ?

The answer to this question can help sell the idea of OOP to project leaders that have no special interest in code quality. At least they could buy the idea if one shows them the kind of things that are not even possible unless you use OOP.

Community
  • 1
Tulains Córdova
  • 39,201
  • 12
  • 97
  • 154
  • 14
    Every program could be written in assembly with no design paradigm applied whatsoever if desired. Don't believe the idea that something isn't possible without one thing or another, it's just a matter of what tools work well for a given problem, the wrong tools will always *work* too, unfortunately. – Jimmy Hoffa Oct 29 '12 at 16:21
  • @JimmyHoffa: luckily, using the wrong tools often leads to such an enormous increase in work that people still use the right (or at least *better*) tools out of laziness ;-) – Joachim Sauer Oct 29 '12 at 16:24
  • 3
    http://en.wikipedia.org/wiki/Turing_completeness – jk. Oct 29 '12 at 16:25
  • 1
    Be careful not to try "selling" OOP to programmers who are using a better paradigm for the problem at hand :) Also, I wonder whether OOP need evangelizing anymore... Even junior programmers these days know about it and try to use it by default. – Andres F. Oct 29 '12 at 16:32
  • @JimmyHoffa I changed the title of the question to make it more flexible. – Tulains Córdova Oct 29 '12 at 16:33
  • 2
    What manager is out there saying "You're not allowed to use OOP?" – Robert Harvey Oct 29 '12 at 16:37
  • @RobertHarvey I meant project leaders. Changed it. – Tulains Córdova Oct 29 '12 at 16:38
  • @RobertHarvey One of the problems is that OOP seems to require more experienced or better programmers which are more expensive and hard to find. It's "cheaper" to hire junior programmers with no OOP knowledge. So for some leaders OOP is a luxury they can live without. – Tulains Córdova Oct 29 '12 at 16:55
  • How do you write a modern program without any OOP knowledge? Use functional programming? – Robert Harvey Oct 29 '12 at 16:57
  • 1
    @RobertHarvey You can write a web app in PHP without writing a single class. – Tulains Córdova Oct 29 '12 at 17:21
  • 1
    Ah, right. http://www.codinghorror.com/blog/2008/05/php-sucks-but-it-doesnt-matter.html – Robert Harvey Oct 29 '12 at 17:23
  • 3
    "Every program could be written in assembly with no design paradigm applied whatsoever if desired.": You could use a similar reasoning and, to someone who's asked you why when they should use a car, say that they could go anywhere on foot. – Giorgio Oct 29 '12 at 17:35
  • Why would you want to "sell" such a worthless idea? – SK-logic Oct 29 '12 at 17:57
  • 1
    @RobertHarvey, you don't need anything OOPish to write modern, clean, robust code. You'll need modules (preferably first-class), metaprogramming (or at least some form of a generic programming), an expressive and powerful type system, maybe some elements of functional programming. I can't see how OOP can be any better than these tools. – SK-logic Oct 29 '12 at 17:59
  • 1
    @SK-logic: Would such a person be cheaper than one who knows OOP? – Robert Harvey Oct 29 '12 at 18:21
  • 2
    @RobertHarvey, in long term - yes, since such a person will work faster, producing cleaner and more maintainable code, will need much less time debugging and testing, and therefore an amortised cost will be significantly less than a cost of a whole team of OOP coders. – SK-logic Oct 29 '12 at 18:38
  • @SK-logic: Ah yes, but you're talking about project leaders with long-term vision, a characteristic which seems to be absent in the folks the OP is talking about. – Robert Harvey Oct 29 '12 at 18:40
  • @user1598390 That's backwards. OOP is _all_ juniors fresh out of school know, the One True Way that's taught everywhere almost by default. On the contrary, better solutions (as suggested by SK-logic in the comments) are _way harder_ to promote in the workplace. Everyone knows about OOP, or at least thinks they practice it. Talk about almost any other paradigm and you'll get puzzled looks. – Andres F. Oct 29 '12 at 21:54
  • @andres-f Maybe lack of OOP proficiency in the job market is a third world (where I live) problem, even though they teach it in universities. Also looking at the questions posted in this site makes me think a lot of people have problems grasping OOP concepts. – Tulains Córdova Oct 29 '12 at 22:11
  • @user1598390 Maybe it's specific to your country? I also live in the third world, and almost everyone assumes OOP by default. Granted, sometimes it's "horribly broken OOP" or "what I think must be OOP", or "whatever-Java-does kind of OOP", but nevertheless, few jobs consider the alternatives. By what I mean, indeed a lot of people have trouble grasping OOP concepts (myself included!), but still they assume it must be the default. – Andres F. Oct 29 '12 at 23:00
  • @Giorgio he is not asking when should he use a car though he is asking when is it impossible to walk – jk. Oct 30 '12 at 09:34
  • @jk: That's why I think one should not answer: "In principle, you can always walk." – Giorgio Oct 30 '12 at 09:41

3 Answers3

6

What kind of programs cannot be written unless you use OOP?

Because of Turing completeness there are none.

What kind of programs are not recommended to be written using non-OOP techniques? What kind of programs need OOP in order to even be written? What kind of programs would be too hard to write without OOP ?

OOP is a good when you have "natural" objects: GUI buttons, files, sockets, locks, etc. In pretty much every non OO language out there you see these opaque object wannabes called handles.

OOP is a mismatch when the design turns towards data transformation processes and doing things. You get stuck in Yegge's Kingdom of Nouns. Basically anytime you have a verb-able, or a verb-er you have strayed past the bounds of good taste in OO land.

That is why multi-paradigm languages are the way to go OO isn't the best tool for every job nor is any other approach. Not only that but there are relatively few applications that are single approach appropriate. So what we currently do is look at which approach is best for 70% of your app then shoe horn the other 30% into some horrible against the grain swamp monster of poor design.

gnat
  • 21,442
  • 29
  • 112
  • 288
stonemetal
  • 3,371
  • 16
  • 17
5

Technically, there are no problems in the field of computer science that cannot be solved without OOP. Object-oriented principles generally define the layout and architecture of source code; once the code is compiled into assembly language for consumption by the CPU, most of the patterns of OOP disappear.

However, since so many modern languages are designed to be object-oriented, a program written in such a language that doesn't make use of the built-in support for OOP may actually require more effort than simply building the program using the tools available. Managed-memory environments like the Java/Dalvik VM and .NET CLR typically use languages designed from the ground up to be O-O, and there's no way to escape it; at the very least, you need the object that contains the main() method (and any subroutines it calls).

As far as programs that require object-oriented architecture, I think the ones that come closest are event-driven GUI programs. The frameworks given by the GUI SDKs are object-oriented, and while I'm sure you can write a CLR program composed entirely of hooks into unmanaged Windows API code to create and display windows and react to the user's input in those windows, the overarching question I would pose faced with any such attempt is, "WHY!?", when the framework presents you with the objects representing all the GUI controls, each one handling the basics and most of the advanced usage scenarios in a neat, tidy package?

That's the strength of object-oriented programming; the "black-box concept". You don't have to care how anything is actually done; you simply care that it is done when you want it to. Why hook into a dozen Windows API functions and make hundreds of calls to display a window on the screen, when you can just call Form.Show()?

As far as convincing management that OOP is a good thing, the argument is all about time. OOP was designed to save the developer's time by increasing code reuse. General-purpose code-objects, which already exist so you don't have to rewrite them, are derived and combined into the specific solution to your particular programming problem. Those objects are also modular (if you follow the Gang of Four design patterns which encourage adherence to design principles like GRASP or SOLID), meaning if a piece of software has a problem (doesn't have to be a bug; programs get updated based on new requirements all the time, and the reason for a software update is a "problem", otherwise you wouldn't be updating the software), the line(s) of code responsible for the current behavior and which must change to exhibit the new behavior are easy to find, easy to change, and, if necessary, easier to replace wholesale than lines of procedural "spaghetti code".

In software development, time is money; there are few if any direct materials costs for a software solution (mostly start-up costs), so the primary driver of the cost of a piece of software is how many developer-hours it takes to create it. Following OOP, I guarantee you, will require fewer developer-hours for any non-trivial program than ignoring it.

KeithS
  • 21,994
  • 6
  • 52
  • 79
  • @ Keiths Good answer. One of the problems is that OOP seems to require more experienced or better programmers which are more expensive and hard to find. It's "cheaper" to hire junior programmers with no OOP knowledge. So for some leaders OOP is a luxury they can live without. – Tulains Córdova Oct 29 '12 at 16:52
  • @user1598390: As has been mentioned, OOP is drilled into most students of software programming; the idea that software is built out of encapsulated objects is central to any course of study beyond the first semester of computer coding, which is typically focused at making the coder think in small enough steps that the computer can follow the logic. While we all start somewhere, a development department composed primarily or exclusively of junior coders is a failure waiting to happen; I have personally seen the results of such an endeavor and the costs of cleaning up. – KeithS Oct 29 '12 at 16:59
  • @user1598390: personally, I would call "a junior programmer without any OOP knowledge" a very unexperienced programmer - and I find it very unlikely that such a person will be "cheaper" if you look at the ratio "programming problems solved"/"salary". – Doc Brown Oct 29 '12 at 17:12
  • @DocBrown This "cheap" programmers have to finish their tasks even if they have to stay late and they aren't paid extra hours. – Tulains Córdova Oct 29 '12 at 17:29
  • overall good answer, except I would argue OOP arose for different reasons, code reuse was a consequence of OOP. OOP was created because it made life easy for management to manage 20 groups of 5 programers working on different objects of the project, than to manage 100 developers working on the project. – Ryathal Oct 29 '12 at 17:42
  • @user1598390: you cannot gain a productivity boost of a factor 5 to 10 by letting your team stay late and work overtime. But you can get such an increase by hiring experienced programmers. – Doc Brown Oct 29 '12 at 18:02
  • 1
    There is no OOP in Tcl/Tk. No OOP in functional reactive graphics. No OOP in XAML. Why would you need OOP for GUI? Following OOP you'll need more developer-hours and you'll certainly increase maintenance costs. It is wise to avoid using OOP in any decently non-trivial project. – SK-logic Oct 29 '12 at 18:03
  • No OOP in XAML? Are you kidding? XML of any type is *inherently* object-oriented; XML was created to provide a universal object-oriented data definition standard. – KeithS Oct 29 '12 at 18:40
  • 1
    @user1598390: 'Have to finish their tasks' is fine until they are simply unable to proceed, either from lack of knowledge and vision, or because they have created such a huge pile of WTF that the development velocity is zero. – kevin cline Oct 29 '12 at 19:48
  • 2
    @KeithS First time I heard XML being called OO. I guess for some horrible broken definition of OO it can be. – Andres F. Oct 29 '12 at 21:59
  • 1
    @KeithS, XAML is, essentially, a huge set of mutually recursive algebraic data types (as any other complex XML language). There are no "objects" exchanging "messages". It is a domain-specific language with a very specialised semantics. – SK-logic Oct 30 '12 at 09:31
2

OO is a way to organize programs. To make the case for OO, you need a big enough program that its organization is important (yes beginners are now drilled into OO way of thinking without any experience of programs big enough for it to matter, but those I meet often are like you, unable to explain why it is good, and thus unable to see when it isn't).

Obviously it doesn't depend only of the size of the program (with which metric BTW), but also a lot of what the program do. The easiest case of OO is probably simulators, there the OO way of thinking maps so cleanly to the problem domain that it is difficult to argue against. As a matter of fact, it was one of the use cases behind OO (Simula is one of the first OO language and it brought language support for techniques already in used but not formalized, and C++ started with the intention to reduce Simula's overhead).

Now, you'll have a very hard time to sell OO to a project leader experienced enough to see that what you are working on is a case where OO brings just overhead without compensating benefits.

AProgrammer
  • 10,404
  • 1
  • 30
  • 45
  • `like you, unable to explain why it is good` I can, and have worked of big projects, but the points I make are not important for many project leaders: smaller code, more clean code, maintainability, etc. They only care about how fast you can code an app that cat run. They measeure how many "screens" you can create in a week. They equal "screens count" to project size. – Tulains Córdova Oct 29 '12 at 16:43
  • See my answer; OOP creates code that is easier to re-use, so the general-purpose code behind one screen can be abstracted into a base class that can then be used to create the next screen. The less you have to rewrite, the faster you can create new screens. – KeithS Oct 29 '12 at 16:48
  • 3
    From a workplace perspective, if the manager of a development team cannot intuitively grasp the advantages of OOP from both a developer and business perspective, *get out now*; this is a *huge* red flag of a bad place to be a coder. – KeithS Oct 29 '12 at 16:49
  • 1
    @user1598390 But OOP doesn't necessarily result in cleaner or smaller code; sometimes it's quite the opposite! You'll need better arguments if you want to convince your project leaders to use it. – Andres F. Oct 29 '12 at 22:01
  • `You'll need better arguments` That's precisely why I posted the question. – Tulains Córdova Oct 29 '12 at 22:08
  • @KeithS, I could not see *any* advantages of OOP ever since it started to gain hype. I only saw numerous disadvantages and WTFs caused by severe misuse of this narrow, highly specialised and exceptionally rarely useful model. OOP is a cancer for the modern IT industry. – SK-logic Oct 30 '12 at 09:35
  • @KeithS, OOP "creates code that is easier to re-use" than what? Easier than highly modular generic code? I always thought OOP is exceptionally bad for code re-use. That was one of the reasons why generic programming started to gain momentum (and it is quite incompatible with OOP in general). – SK-logic Oct 30 '12 at 09:43
  • 1/ "intuition" is often just "correspond to my prejudice" 2/ "clean" is often just "familiar" and not an absolute quality. 3/ There are cases where OO makes no sense from one of the technical or business POV, people who refuse to admit that tends to complicate the life those who want to use OO when it makes sense even more than those who refuse to admit OO makes sometimes sense. 4/ If my experience is applicable, nowadays has so much influence that when someone doesn't want to use OO, it has more often than not valid reasons, but some GP proponents are trying to inverse the tendency. – AProgrammer Oct 30 '12 at 09:58
  • 5/ Now, I've made friends. ;) Don't worry I've out of Internet access for some days. – AProgrammer Oct 30 '12 at 09:58