封装和抽象之间的确切区别是什么?
当前回答
抽象让您关注对象做了什么，而不是它是如何做的 封装意味着隐藏对象如何做某事的内部细节或机制。
就像你开车时，你知道油门踏板的作用，但你可能不知道它背后的过程，因为它是封装的。
让我用c#举个例子。假设你有一个整数:
int Number = 5;
string aStrNumber = Number.ToString();
你可以使用像number . tostring()这样的方法，它返回数字5的字符表示，并将其存储在字符串对象中。该方法告诉您它做了什么，而不是如何做。
其他回答
让我们以堆栈为例。它可以使用数组或链表来实现。但它支持的操作是推送和弹出。
Now abstraction is exposing only the interfaces push and pop. The underlying representation is hidden (is it an array or a linked list?) and a well-defined interface is provided. Now how do you ensure that no accidental access is made to the abstracted data? That is where encapsulation comes in. For example, classes in C++ use the access specifiers which ensure that accidental access and modification is prevented. And also, by making the above-mentioned interfaces as public, it ensures that the only way to manipulate the stack is through the well-defined interface. In the process, it has coupled the data and the code that can manipulate it (let's not get the friend functions involved here). That is, the code and data are bonded together or tied or encapsulated.
抽象是广义的术语。即封装是抽象的子集。
| Abstraction | Encapsulation |
|---|---|
| It solves an issue at the design level. | Encapsulation solves an issue at implementation level. |
| hides the unnecessary detail but shows the essential information. | It hides the code and data into a single entity or unit so that the data can be protected from the outside world. |
| Focuses on the external lookout. | Focuses on internal working. |
| Lets focus on what an object does instead of how it does it. | Lets focus on how an object does something. |
| Example: Outer look of mobile, like it has a display screen and buttons. | Example: Inner details of mobile, how button and display screen connect with each other using circuits. |
示例:解决方案架构师是创建整个解决方案的高级抽象技术设计的人，然后将该设计移交给开发团队进行实现。 在这里，解决方案架构师充当抽象，而开发团队充当封装。
举例:用户数据的封装(组网)
图片由
Abstraction (or modularity) – Types enable programmers to think at a higher level than the bit or byte, not bothering with low-level implementation. For example, programmers can begin to think of a string as a set of character values instead of as a mere array of bytes. Higher still, types enable programmers to think about and express interfaces between two of any-sized subsystems. This enables more levels of localization so that the definitions required for interoperability of the subsystems remain consistent when those two subsystems communicate. Source
Java示例
抽象是对用户隐藏无用的数据 封装是将数据绑定到一个胶囊(类)中。 我认为封装是我们实现抽象的方式。
许多答案和例子都具有误导性。
封装是将“数据”和“对该数据进行操作的函数”打包到单个组件中，并限制对某些对象组件的访问。 封装意味着对象的内部表示通常隐藏在对象定义之外的视图中。
抽象是一种表示基本特性而不包括实现细节的机制。
封装:——信息隐藏。 抽象:——实现隐藏。
示例(c++):
class foo{
private:
int a, b;
public:
foo(int x=0, int y=0): a(x), b(y) {}
int add(){
return a+b;
}
}
foo类的任何对象的内部表示都隐藏在该类的外部。——>封装。 foo对象的任何可访问成员(data/function)都是受限的，只能由该对象访问。
foo foo_obj(3, 4);
int sum = foo_obj.add();
方法add的实现是隐藏的。——>抽象。
抽象—隐藏实现—在设计—使用接口/抽象类
封装—隐藏数据—在开发时—使用访问修饰符(公共/私有)
