STL::list 中的 C++ 接口(interface)

Question

类(class)界面

class ILesson
{
    public:
        virtual void PrintLessonName() = 0;
        virtual ~ILesson() {}
};

STL容器

typedef list<ILesson> TLessonList;

调用代码

for (TLessonList::const_iterator i = lessons.begin(); i != lessons.end(); i++)
    {
        i->PrintLessonName();
    }

错误:

Description Resource Path Location Type passing ‘const ILesson’ as ‘this’ argument of ‘virtual void ILesson::PrintLessonName()’ discards qualifiers

Answer 1

PrintLessonName 必须声明为 const 才能在 const ILessons 上调用。否则，编译器假定它可能会修改 ILesson 并阻止调用。

virtual void PrintLessonName() const = 0;