c ++ iterator

ExpressionReturn TypePrecondition*rreferencer is dereferenceable (see below)++rIt&r is incrementable (see below)

迭代器(Iterator)是用来遍历容器中的每一个元素。迭代器可以被认为一个抽象的指针。

Dereferenceable iterators 解引用迭代


Iterators for which the behavior of the expression *i is defined are called dereferenceable.

Iterators are not dereferenceable if：

1、they are past-the-end iterators or before-begin iterators.
2、they were invalidated by one of the iterator-invalidating operations on the sequence to which they refer.

iterators for which the behavior of the expression ++i is defined are called incrementable.

在迭代器中使用 ++i,返回新的迭代器。