双端队列迭代器 [英] deque iterators

问题描述

我创建了一个具有双端队列对象的模板类.我很少希望能够访问std :: deque :: iterator对象.但是，我一直无法获得一个非常简单的示例来工作...关于如何解决它的任何想法?
我有一个使用受保护的和私有继承的示例，但是出于性能原因和通用性考虑，如果我的类具有多个双端队列/向量，我更喜欢分层.此外，通过分层，我隐藏了更多的实现细节...

第一次尝试

I created a template class that has a deque object. I infrequently want to be able access the std::deque::iterator object. However, I have been unable to get a very simple example to work... Any ideas how to fix it?
I have an example working now using protected and private inheritance, but I would prefer layering for performance reasons and generality if my class has more than one deque/vector. Moreover, with layering, I had hide more implementation details...

1st try

template<typename T>
class XYZ {
std::deque<T> B;
....
public:
std::deque<T>::iterator begin() { return B.begin(); }
);

警告C4346:``std :: deque< Task> :: iterator'':从属名称不是类型
错误C2146:语法错误:标识符开始"之前缺少;"

第二次尝试

warning C4346: ''std::deque<Task>::iterator'' : dependent name is not a type
error C2146: syntax error : missing '';'' before identifier ''begin''

2nd try

template<typename T>
class XYZ {
std::deque<T> B;
....
public:
std::_Deque_iterator<T, std::allocator< std::deque<T> > > begin() { return B.begin(); }
};

错误消息:

错误C2440:``正在初始化'':无法从``std :: _ Deque_iterator< _Ty，_Alloc>''转换为``std :: _ Deque_iterator< _Ty，_Alloc>''

Strange error message:

error C2440: ''initializing'' : cannot convert from ''std::_Deque_iterator<_Ty,_Alloc>'' to ''std::_Deque_iterator<_Ty,_Alloc>''

推荐答案

泰德，
不太了解为什么要公开它，无论如何都应编译:

Hi Ted,
Not really understanding why you want to expose that, anyhow this should compile:

typename std::deque<T>::iterator begin()
{
    return B.begin();
}

欢呼声，
AR

cheers,
AR

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