64Digits

I just don't get it.

People treat the programmer that is using their code like an ordinary user. They treat you like you have no idea whatsoever about any kinds of programming concepts, and like you need everything to be spoon-fed to you through a list of implementation functions.

class point2d
{
  private:
    double x, y;

  public:
    double get_x() { return x; }
    double get_y() { return y; }
    
    void get_x(double val) { x = val; }
    void get_y(double val) { y = val; }
};

versus:

struct point2d
{
  double x, y;
};

The first completely ruins my ability to do useful things, such as pt.x += 1. Instead, I have to do pt.set_x(pt.get_x() + 1). Granted, you can still add operators and such to this if you're using C++ (not in Java) or add functions like add_x and add_y, but you have to then ask why the hell that you thought of this in the first place.

Even for things like strings, I don't really get it. I mean, yeah, it's kind of pointless to make an array class which stores a pointer and an integer for length and then just modify the pointer directly. But it's stupid to "hide" this from the user when the user clearly knows that it's there, and to provide get() and set() functions which essentially allow you to modify the variable directly.

I do understand if you're trying to only allow getting a value, but if it's just another programmer using it, why hide it? It's not like making the variables in a point class magically enable users to edit the points that are being used by the program. It's not like users would be able to access your database info if it's made public unless you're allowing them to execute PHP - in which case, you've already allowed the user to bypass anything.

I mean, in the programming concepts in my Java class, they use examples in things like bank accounts. They make a class called BankAccount and add withdraw(), deposit(), and a constructor. But the variable containing the money is private. The rationale? We don't want you editing the money the BankAccount directly!!!

But uh, it's already being done directly. If withdraw() and deposit() were functions that inputted PIN numbers and such to validate things or had limits, I'd be fine with that. But they're not. You're directly modifying stuff, and I don't see why you have to hide a number from me but let me edit it indirectly.

I mean, even if the implementation is confusing, there's no reason to hide it. Oftentimes, the implementation is essentially defined by member functions - for example, std::vector has size() and capacity(). This already tells me that somewhere, there is a stored size and a stored capacity. And, it stores a dynamically-sized array, which tells me that it contains a pointer to said array. I've already identified the vector implementation.

While the functions that are implemented may be changed, the data itself never changes. Why is it kept hidden? If I go messing into it and break the vector because of modified data, then that's my fault. But I don't see why you have to hide it from me.

I'm too lazy to write a conclusion, so, there you go.

PY 13 years, 8 months ago

I think you're suffering from "I know best" syndrome, here, your major complaint seems to be that it hides information from you. This is a good thing, the specific implementation details of something are completely unimportant, the only thing that matters is that it does what it does. How it does that, well, you don't need to know. If you want to know, go take a look, but the details are insignificant and will only serve to bog you down. Abstraction isn't just for the user, it's for everyone, nobody can comprehend the entirety of a complex application at the same time, nor should there ever be a need to.

Encapsulation

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