说明：  使用C++做的双链表模板类 具有头插法，尾插法，左向插入，右向插入，删除结点，获取结点值，设置结点值，复制构造函数，还重载了输出操作符、赋值操作符、相等操作符和不等操作符，还具有倒置链表的功能。还有结点类的重载的输出操作符，具有很好的封装性。
(Using C++ to do the double linked list template class with the first interpolation method, tail interpolation, left to insert the right to insert, delete nodes, for node value set node value, copy constructor, also overloaded output operator , assignment operator, equality operator and the range operator, which also has the inverted list of features. Node class are overloaded output operator, has a good encapsulation.)