std::ranges::elements_view<V,N>::iterator<Const>::operator++,--,+=,-=
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                    < cpp | ranges | elements view | iterator
                    
                                                            
                    | constexpr /*iterator*/& operator++(); | (1) | (C++20 起) | 
| constexpr void operator++( int ); | (2) | (C++20 起) | 
| constexpr /*iterator*/ operator++( int ) requires ranges::forward_range<Base>; | (3) | (C++20 起) | 
| constexpr /*iterator*/& operator--() requires ranges::bidirectional_range<Base>; | (4) | (C++20 起) | 
| constexpr /*iterator*/ operator--( int ) requires ranges::bidirectional_range<Base>; | (5) | (C++20 起) | 
| constexpr /*iterator*/& operator+=( difference_type n ) requires ranges::random_access_range<Base>; | (6) | (C++20 起) | 
| constexpr /*iterator*/& operator-=( difference_type n ) requires ranges::random_access_range<Base>; | (7) | (C++20 起) | 
增或减迭代器。
令 current_ 为底层迭代器。
1) 等价于 ++current_; return *this;
2) 等价于 ++current_;
3) 等价于 auto tmp = *this; ++*this; return tmp;
4) 等价于 --current_; return *this;
5) 等价于 auto tmp = *this; --*this; return tmp;
6) 等价于 current_ += n; return *this;
7) 等价于 current_ -= n; return *this;
参数
| n | - | 相对于当前位置的位置 | 
返回值
1,4,6,7) *this
2) (无)
3,5) 更改前的 *this 的副本