在另一个类中使用变量 [英] Use variable in another class

问题描述

B类在A类中实例化:

Class B is instantiated in class A:

Class A {
int x, y;

B b;
}

我如何才能从类B的成员函数中使用变量x和y?

How can I use variables x and y from member functions of class B?

推荐答案

我认为，如果您获得有关类设计的更多知识，那就更好了. > 因此，我希望您能看一看C ++的书籍，例如Stanley B Lippman的C ++ Primer.

好吧，看你的情况

I think, it better if you get some more knowledge regarding class design.
So i prefer you to have a look with some book in C++ like C++ Primer from Stanley B Lippman.

Well see your case

class B
{
public:
  void SetAVal( int X1, int Y1 )
  {
     LocalX = X1;
     LocalY = Y1;
  }
private:
   int LocalX, LocalY;
};

Class A {
int x, y;
void SetValTOB()
{
  b.SetAVal( x, y );
}

B b;
}

您应该购买一本有关C ++的书，并阅读有关面向对象编程的工作方式的章节.您的问题毫无道理.类A没有变量，类A的实例却没有.如果B具有A的实例，则可以访问A中的变量.A在此处具有B的实例，并且可以访问其中的值(如果它们是公共的).您必须将A的实例传递到B的函数中，或直接传递x/y值.否则将无法访问它们.

You should buy a book on C++ and read the chapters on how object oriented programming works. Your question makes no sense. Class A has no variables, instances of class A do. If B has an instance of A, it can access the variables in A. A has an instance of B here, and can access values in it, if they are public. You''d have to pass the instance of A into the function in B, or pass the x/y values in directly. It can''t access them otherwise.

您不能在任何其他类中直接使用A中声明的变量，无论是否嵌套.您将必须传递A的实例，然后使用A的成员函数访问其变量.

-Saurabh

You cannot directly use variables declared in A in any other class, whether nested or not. You will have to pass an instance of A and then use member functions of A to access its variables.

-Saurabh

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