c++ - 访问不明确的类成员

Question

我有一颗钻石。我想访问类(class)成员。我正在使用 mingw。
问题是:如何在不重新声明类的情况下访问成员“top::A”

#include <cstdio>
class top {
public:
    const char A;
    top(): A('t') {}
};
class left: public top {
public:
    const char A;
    left():A('l'){}
};
class right: public top {};
class bottom: public left, public right {};

int main() {
    bottom obj;
    printf("%c\n", obj.bottom::right::A); //using right::A, inherited from top::A
    printf("%c\n", obj.bottom::left::A); //using left::A and left::top::A is hidden
    //printf("%c\n", obj.bottom::left::top::A); //error. How to access it?
    return 0;
}

当我删除评论时 mingw 给我一个错误:

'top' is an ambiguous base of 'bottom'  

更新:看起来转换类型有效:

printf("%c\n", static_cast<top>(static_cast<left>(obj)).A);
printf("%c\n", static_cast<left>(obj).::top::A);
printf("%c\n", reinterpret_cast<top&>(obj).A);//considered bad
printf("%c\n", (reinterpret_cast<top*>(&obj))->A);//considered evil
//      printf("%c\n", static_cast<top&>(obj).A);//error

Answer 1

在不使用虚拟继承的情况下，您可以稍微修改类型以说服编译器选择正确的基类:

printf("%c\n", static_cast<left&>(obj).::top::A);