私有/公共标题示例？ [英] Private/public header example?

问题描述

有人可以给我一个公共和私有头文件如何工作的例子吗？我已经在网上进行了一些阅读，但似乎找不到包含示例代码的有用信息。有人建议我使用私有头将代码的公共部分和私有部分分开，以创建静态库。阅读一番之后，我对它的工作原理有了一个大致的了解，但真的很感谢一个很好的例子让我入门。具体来说，我不太了解如何将接口函数放在公共标头中，而如何将私有变量/函数放在私有标头中？谢谢！

Can someone please give me an example of how public and private headers work? I have done some reading on the net but I can't seem to find much useful information with sample codes. I was advised that I should use private headers to separate the public and private parts of my code for creating a static library. After some reading I have a general idea of how it works, but would really appreciate a good example to get me started. Specifically, what I don't quite understand is how to put the interface functions in my public header, and the private variables/functions in my private header? Thanks!

编辑：

也许我不是在说我正确的问题，但是我的意思是，例如，我有myMath.h和myMath.cpp，而myMath.h有：

Maybe I'm not wording my question right, but what I meant is, for example, I have myMath.h and myMath.cpp, and myMath.h has:

class myMath{
public:
    void initialise(double _a, double _b);
    double add();
    double subtract();

private:
    double a;
    double b;
};

myMath.cpp具有函数的实现。如何使myMath.h仅具有三个公用函数，并在另一个文件（例如myMath_i.h）中定义私有变量，并且这三个文件的方式是在创建静态库之后，用户只需要myMath.h。这也意味着myMath.h不能#include myMath_i.h。就像这样：

And myMath.cpp has the implementations of the functions. How can I make it so that myMath.h only has the three public functions, and the private variables are defined in another file (e.g. myMath_i.h), and these three files are in such a way that after I create a static library, only myMath.h is needed by users. This also means myMath.h cannot #include myMath_i.h. So something like:

myMath.h：

class myMath{
public:
    void initialise(double _a, double _b);
    double add();
    double subtract();
}

和myMath_i.h：

and myMath_i.h:

class myMath{
private:
    double a;
    double b;
}

当然不可能，因为那样的话我将重新定义类myMath。 ..

Of course that's not possible because then I'll be redefining the class myMath...

推荐答案

您有两个头文件MyClass.h和MyClass_p.h，以及一个源文件：MyClass.cpp。

You have two header files MyClass.h and MyClass_p.h and one source file: MyClass.cpp.

让我们看一下其中的内容：

Lets take a look at what's inside them:

MyClass_p.h：

MyClass_p.h:

// Header Guard Here
class MyClassPrivate
{
public:
    int a;
    bool b;
    //more data members;
}

MyClass.h：

MyClass.h:

// Header Guard Here
class MyClassPrivate;
class MyClass
{
public:
    MyClass();
    ~MyClass();
    void method1();
    int method2();
private:
    MyClassPrivate* mData;
}

MyClass.cpp：

MyClass.cpp:

#include "MyClass.h"
#include "MyClass_p.h"

MyClass::MyClass()
{
    mData = new MyClassPrivate();
}

MyClass::~MyClass()
{
    delete mData;
}

void MyClass::method1()
{
    //do stuff
}

int MyClass::method2()
{
    return stuff;
}

将数据保留在MyClassPrivate中并分发MyClass.h。

Keep your data in MyClassPrivate and distribute MyClass.h.

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