0001 template <typename T> void List<T>::reverse() { //前后倒置
0002    ListNodePosi<T> p = header; ListNodePosi<T> q = trailer; //头、尾节点
0003    for ( Rank i = 1; i < _size; i += 2 ) //（从首、末节点开始）由外而内，捉对地
0004       swap( ( p = p->succ )->data, ( q = q->pred )->data ); //交换对称节点的数据项
0005 }