您好,登录后才能下订单哦!
密码登录
登录注册
点击 登录注册 即表示同意《亿速云用户服务条款》
#pragma once struct InputIteratorTag {}; struct OutputIteratorTag {}; struct ForwardIteratorTag : public InputIteratorTag {}; struct BidirectionalIteratorTag : public ForwardIteratorTag {}; struct RandomAccessIteratorTag : public BidirectionalIteratorTag {}; template<class T> struct InputIterator { //typedef T ValueType; //typedef Distance DifferenceType; //typedef T* Pointer; //typedef T& Reference; typedef InputIteratorTag IteratorCategory; //迭代器的类型 ( 包括上面那5个struct ) }; template<class Iterator> struct IteratorTraits { //typedef typename Iterator::ValueType ValueType; //typedef typename Iterator::DifferenceType DifferenceType; //typedef typename Iterator::Pointer Pointer; //typedef typename Iterator::Reference Reference; typedef typename InputIterator<Iterator>::IteratorCategory IteratorCategory; }; template<class T> struct IteratorTraits<T*> //内置类型的特化版本 { typedef RandomAccessIteratorTag IteratorCategory; }; template <class InputIterator> inline size_t Distance(InputIterator first, InputIterator last) { return _Distance(first, last, IteratorTraits<InputIterator>::IteratorCategory() ); //这里第三个参数 并没有实际意义,不过正是它的存在,让_Distance实现重载 } template <class InputIterator> inline size_t _Distance(InputIterator first, InputIterator last, RandomAccessIteratorTag) { return last - first; } template <class InputIterator> inline size_t _Distance(InputIterator first, InputIterator last, InputIteratorTag) { size_t n = 0; while (first != last) { ++first; ++n; } return n; }
免责声明:本站发布的内容(图片、视频和文字)以原创、转载和分享为主,文章观点不代表本网站立场,如果涉及侵权请联系站长邮箱:is@yisu.com进行举报,并提供相关证据,一经查实,将立刻删除涉嫌侵权内容。