好吧，这真的很难承认，但我确实有一个强烈的诱惑，从std::vector继承。
I need about 10 customized algorithms for vector and I want them to be directly members of the vector. But naturally I want also to have the rest of std::vector's interface. Well, my first idea, as a law-abiding citizen, was to have an std::vector member in MyVector class. But then I would have to manually reprovide all of the std::vector's interface. Too much to type. Next, I thought about private inheritance, so that instead of reproviding methods I would write a bunch of using std::vector::member's in the public section. This is tedious too actually.
在这里，我真的认为我可以简单地从std::vector公开继承，但在文档中提供了一个警告，该类不应该多态地使用。我认为大多数开发人员都有足够的能力来理解这无论如何都不应该多态地使用。
我的决定是绝对不合理的吗?如果有，为什么?你能提供一个替代方案，这将有额外的成员实际上成员，但不会涉及重新键入所有矢量的接口?我很怀疑，但如果你能做到，我会很开心的。
而且，除了有些白痴能写出这样的东西
std::vector<int>* p = new MyVector
使用MyVector还有其他现实的危险吗?通过说现实，我放弃了一些东西，比如想象一个函数，它接受一个指向向量的指针…
我已经陈述了我的观点。我有罪。现在就看你是否原谅我了:)
如果你遵循好的c++风格，缺少虚函数不是问题，而是切片(参见https://stackoverflow.com/a/14461532/877329)
为什么虚函数的缺失不是问题?因为函数不应该尝试删除它接收到的任何指针，因为它没有指针的所有权。因此，如果遵循严格的所有权策略，就不应该需要虚拟析构函数。例如，这总是错误的(有或没有虚析构函数):
void foo(SomeType* obj)
{
if(obj!=nullptr) //The function prototype only makes sense if parameter is optional
{
obj->doStuff();
}
delete obj;
}
class SpecialSomeType:public SomeType
{
// whatever
};
int main()
{
SpecialSomeType obj;
doStuff(&obj); //Will crash here. But caller does not know that
// ...
}
相反，这将始终工作(使用或不使用虚析构函数):
void foo(SomeType* obj)
{
if(obj!=nullptr) //The function prototype only makes sense if parameter is optional
{
obj->doStuff();
}
}
class SpecialSomeType:public SomeType
{
// whatever
};
int main()
{
SpecialSomeType obj;
doStuff(&obj);
// The correct destructor *will* be called here.
}
如果该对象是由工厂创建的，工厂还应该返回一个指向工作删除器的指针，应该使用该指针而不是delete，因为工厂可能使用自己的堆。调用者可以以share_ptr或unique_ptr的形式获取它。简而言之，不要删除不是直接从new中获取的任何内容。
There is no reason to inherit from std::vector unless one wants to make a class that works differently than std::vector, because it handles in its own way the hidden details of std::vector's definition, or unless one has ideological reasons to use the objects of such class in place of std::vector's ones. However, the creators of the standard on C++ did not provide std::vector with any interface (in the form of protected members) that such inherited class could take advantage of in order to improve the vector in a specific way. Indeed, they had no way to think of any specific aspect that might need extension or fine-tune additional implementation, so they did not need to think of providing any such interface for any purpose.
The reasons for the second option can be only ideological, because std::vectors are not polymorphic, and otherwise there is no difference whether you expose std::vector's public interface via public inheritance or via public membership. (Suppose you need to keep some state in your object so you cannot get away with free functions). On a less sound note and from the ideological point of view, it appears that std::vectors are a kind of "simple idea", so any complexity in the form of objects of different possible classes in their place ideologically makes no use.
