c++ - 如何在C++中的子类的构造函数中初始化父类(super class)的const成员变量？

Question

我有以下情况，我声明了 父类(super class) 的 const 成员，现在我想在其 子类之一的构造函数中初始化它 使用列表初始值设定项。

struct Shape {
public:
    const Rect boundingRect; // the rect in which the shape is contained
};

struct Stain : Shape
{
public:
    Stain(Rect boundingRect_) : boundingRect(boundingRect_) {}
};

我不确定这是否可行，如果我采用上面显示的直接方法，编译器会报错并显示以下消息:

member initializer 'boundingRect' does not name a non-static data member or base class

This answer解释了为什么不可能在子类 构造函数的list initiliazers 中初始化父类(super class)的成员变量。我想知道针对这种情况的最佳做法是什么？

Answer 1

您必须为 struct Shape 添加一个构造函数，并从您的子类中调用它。像这样:

struct Shape {
public:
    const Rect boundingRect; // the rect in which the shape is contained

    Shape( Rect rect ) : boundingRecT( rect ) {}
};

struct Stain : Shape
{
public:
    Stain(Rect boundingRect_) : Shape (boundingRect_) {}
};