OOP and the scope of a class, am I wrong?
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
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Of course, but I was simplifying and glossing over details to simply get to the larger point, to wit: In my mind, a class is a noun, not a verb, essentially.
Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
honey the codewitch wrote:
In my mind, a class is a noun, not a verb, essentially
For me, a class may be either a noun or a verb. As a noun, the concept represented by the class is a thing, and the class provides information and operations for that thing. For a verb the concept is a process, and the class supports that process. I guess 'process' can be thought of as a noun, but thinking of it that way adds indirection to my thinking.
Software Zen:
delete this; -
My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
No, you are correct. Your car is a valid class as you define it. ReadTextFile() is a function. To be a valid class, imo, it would be TextFile as the class, with properties and actions. TextFile.length, etc. and TextFile.Read,write,etc. My take, in English grammar, is that a class should be a noun, with adjectives, verbs and possibly adverbs that go with it. If it's short of that, it deserves another look for consideration as a function or structure. I suppose, depending on the language, a class could be looked at as a convenient way to store a reusable. What a declaration nightmare that creates, using your example.
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
honey the codewitch wrote:
But I'm hearing that professors are teaching that classes are effectively a single action like ReadTextFile and it makes me a lot more irritated than I probably should be.
You're right. A class encapsulate a physical or logical object, including ways to interact with the object. What that professor is teaching is sheer idiocy. Many moons ago a friend relayed a story -- we worked for a consulting firm and he did the tech interview for a professor that had taught VB at the local community college for 5 years. She failed the interview and he recommended against hiring her. Why? She knew the syntax of the language better than he did, but she had NO idea how to actually program. She could answer questions such as "which method to use to add an item to a listbox" (something we didn't bother asking), but didn't know which construct to use for looping. She could write an if loop, but couldn't tell when to use if or while or foreach. He went into the interview assuming it was a formality, and ended up vetoing her. Far too many college professors have no real world experience.
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He designed C++ not OOP
In a closed society where everybody's guilty, the only crime is getting caught. In a world of thieves, the only final sin is stupidity. - Hunter S Thompson - RIP
But he explained OOP that way and the implmentation in C++ was that way as well.
I’ve given up trying to be calm. However, I am open to feeling slightly less agitated. I’m begging you for the benefit of everyone, don’t be STUPID.
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
I`d say no you are not wrong, but the teacher is not necessarily wrong either. A class can be almost anything in C++. - Can be an interface - Can be a functor - Can be just data - Whatever... so, depending on how the teacher wants the thing to evolve he might direct his students. with very little or no context it is hard to decide who's right. If you are using class to model things, they can be names. If they model actions, they can be verbs. If they model attributes, they can be adjectives. classes are one of the mechanisms for encapsulation & data hiding after that, when I do code review, I usually check the coupling between the class and the client, this usually tells me if the data hiding or encapsulation is at a proper level or done right.
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Personally I can't make a bridge between ReadTextFile and the car... Anyway you example shows a classic thing, that classes are usually not 'stand alone' and in a certain way 'connected'/'depended' Your examlpe: Engine.Start() does depend on the state of the Gear. Either Engine asks the gear for 'I'm ready to start' or the gear sends a message to the engine 'hey, I'm at gear 1 (without pressed clutch), not really good to start at the moment' and so on and on and on... Abstracting the reality is usually very hard. Only my two cents.
0x01AA wrote:
Abstracting the reality is usually very hard.
Abstracting reality may be difficult but its absolutely essential. If you see a chair that you've never seen before and you don't have an abstract concept of what a chair is, how would you ever know its a chair? It sounds like this professor had a difficult time with the abstract concept of a class. It can be a difficult concept but I would think it would be a prerequisite to being an IT professor. But what do I know? I'm self taught and assume there a plenty of abstract concepts I'm just not aware of.
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Mixing (up) function(s) and actions. ReadTextFile is some clumsy rewording of a "TextReader" class.
"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
Sounds like someone misunderstood. Those will be some messed up students if they come out thinking classes are/should be SRP. Methods/functions sure, but... OOP tends to be highly overrated when you turn on the ultra pedant. Probably through here, I've read recent articles from others who spit on DRY and recognize that classic OOP has some serious faults.
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
Well, at least we'll never be unemployed!
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
Why does it have to be one or the other? One class could model a physical object like a car while another could model an operation such as a database transaction, file operation, or something more complex. At the end of the day it is about using the tools to minimize the cost of solving problems. And concepts like encapsulation and polymorphism frequently are the best tools for the job.
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
To a large extent the 'normalization' of classes is akin to the normalization of data records. The atomic characteristics of a class, that would drive application decomposition (and vice versa), can vary between applications. Thus a useful class decomposition in one instance can be a dogs breakfast in another. There is a similar problem when looking at communications protocols - doctrine dictates multiple layers but these can severely impede and bloat small systems. As humans show every moment, it is possible to communicate without layers (with varying degrees of success), particularly when context is available. For humans effective communication is possible even when the context is ambiguous. For myself, I have classes that do the equivalent of 'ReadTextFile' or 'ReadComPort' - these typically act as base class for different types of parser such that the data is transformed in some way into an easily digestible form for another part of the app. Whereas one may aspire to a 'universal' set of pattern classes, their utility will generally boil down to adaptation within specific application constraints.
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Sounds like someone misunderstood. Those will be some messed up students if they come out thinking classes are/should be SRP. Methods/functions sure, but... OOP tends to be highly overrated when you turn on the ultra pedant. Probably through here, I've read recent articles from others who spit on DRY and recognize that classic OOP has some serious faults.
The directive in the assignment, which I had a copy of said literally name the class ReadTextFile.
Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
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honey the codewitch wrote:
In my mind, a class is a noun, not a verb, essentially
For me, a class may be either a noun or a verb. As a noun, the concept represented by the class is a thing, and the class provides information and operations for that thing. For a verb the concept is a process, and the class supports that process. I guess 'process' can be thought of as a noun, but thinking of it that way adds indirection to my thinking.
Software Zen:
delete this;That's a good point. I was trying to get to the essence of it and simplify, but obviously I missed the mark in terms of covering every eventuality.
Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
I always split my OOP classes into two parts; classes for actions, and structures\structs for data. I just find it easier that way. I also try to limit what each would hold in the attempt to keep my classes\structures small. In the end, OOP's big advantage is its organizational capabilities within an application. And that organization is primarily up to the developer, not a professor...
Steve Naidamast Sr. Software Engineer Black Falcon Software, Inc. blackfalconsoftware@outlook.com
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The directive in the assignment, which I had a copy of said literally name the class ReadTextFile.
Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
The only reasonable thing I think the professor could have referred to is what Gerry Schmitz above (~3rd from top) referred to
class TextReaderwhich is not insane in the terms of GOF (Design Patterns) but Prof's way of describing it is ofc misleading. e.g.class PngReader : public ImageReader {...
class SvgReader : public ImageReader { ...
"If we don't change direction, we'll end up where we're going"
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The only reasonable thing I think the professor could have referred to is what Gerry Schmitz above (~3rd from top) referred to
class TextReaderwhich is not insane in the terms of GOF (Design Patterns) but Prof's way of describing it is ofc misleading. e.g.class PngReader : public ImageReader {...
class SvgReader : public ImageReader { ...
"If we don't change direction, we'll end up where we're going"
Yeah, and this could have also been CsvReader except it only read a specific CSV with certain columns and datatypes. ReadTextFile is maybe the worst name I could think of for that. =) PatientDataReader would have been better.
Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
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#AdmiralAckbar It's a trap! Hopefully... he's gonna angle that into ok, that was a good start, but... sorta thing.
I explained that while he should do as the assignment requires, a class encapsulates related data and actions, so it really was an inappropriate name for a class. I suggested another name "PatientDataReader" or something (I forget exactly, but it was better) if he was doing it on his own.
Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
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My take: A class should group related data and actions that center around a single concept. A car class might contain 4 Tire class instances as data members, an Engine instance, and a Gearbox instance. Each one has actions relevant to its operation like Engine.Start(), and Wheel.Rotate() But I'm hearing that professors are teaching that classes are effectively a single action like
ReadTextFileand it makes me a lot more irritated than I probably should be. Am I wrong here?Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix
You are right. A class should represent some definable entity, whether atomically (e.g. Tire class) or in the aggregate of related entities (Car class that inherits Vehicle class, containing a Tire class collection, Engine class, Transmission class, etc.). Whatever "professors" that are saying what you report need to go get their hands dirty writing and supporting production software to test their theories before opening their mouths to sound foolish.
