从子类方法访问基类变量 [英] Access Base class variable from child class method

问题描述

如何从子方法访问基类变量?我遇到了分段错误.

How can I access base class variable from a child method? I'm getting a segmentation fault.

    class Base
    {
    public:
        Base();
        int a;
    };

    class Child : public Base
    {
    public:
        void foo();
    };

    Child::Child() :Base(){

    void Child::foo(){
        int b = a; //here throws segmentation fault
    }

在另一个班级:

    Child *child = new Child();
    child->foo();

推荐答案

将类变量公开不是一个好习惯.如果你想从 Child 访问 a 你应该有这样的东西:

It's not good practice to make a class variable public. If you want to access a from Child you should have something like this:

class Base {
public:
  Base(): a(0) {}
  virtual ~Base() {}

protected:
  int a;
};

class Child: public Base {
public:
  Child(): Base(), b(0) {}
  void foo();

private:
  int b;
};

void Child::foo() {
  b = Base::a; // Access variable 'a' from parent
}

我也不会直接访问 a.如果你为 a 创建一个 public 或 protected getter 方法会更好.

I wouldn't access a directly either. It would be better if you make a public or protected getter method for a.

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