从另一个类调用类方法 [英] calling a class method from another class

问题描述

我想在类A的方法成员中更改类B的变量成员。
示例：

I want to change a variable member of class B, in a method member of class A. Example:

A.h:
class A
{
    //several other things
    void flagchange();
}
A.cpp:
void A::flagchange()
{
    if (human) Bobj.flag=1;
}

我知道我需要一个B类的对象来更改一个可变成员但是B中的对象在A中是不可达的。可以通过指针来实现。

I know that I need an object of class B, to change a variable member of B, but objects of B are not reachable in A. Is it possible by a pointer??

推荐答案

但B中的对象在A中无法访问

but objects of B are not reachable in A

如果类B的对象无法通过类A访问，可以修改它们。一旦你重构你的设计，你应该将它作为参数传递给函数：

If objects of class B are not reachable by class A there's no way you can modify them. Once you refactored your design, you should pass it as an argument to the function:

class A {
    //several other things
    void flagchange(B& obj) {
        if (human)
            obj.flag = 1;
    }
};

我想要能够从类的方法A的每个对象B

I want to be able to toggle the flag from a method of class A for every object of B

您应该将标志 static in B ：

class B {
public:
    static int flag;
};

int B::flag = 0;

然后，从 A ：

class A {
    //several other things
    void flagchange() {
        if (human)
            B::flag = 1;
    }
};

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