以下是使用其他方法实现的代码：
”`cpp #ifndef NULL #define NULL 0 #endif
#include
// 定义单链表结点结构 struct LNode {
int data;LNode* next;LNode() {};LNode(int e, LNode* n = NULL) :data(e), next(n) {};
};
// 单链表list类创建 class List { protected:
LNode* head;int _size;
public:
// 构造函数List() {head = new LNode;head->next = NULL;_size = 0;}// 析构函数~List() {clear();delete head;}// 头节点List(int info) { // 使用头结点储存某些信息，不随链表插入改变位置head = new LNode(info);_size = 0;}int& info() {return head->data;} // 返回链表头结点的信息void clear() {LNode* p = head->next;while (p){LNode* temp = p->next;delete p;p = temp;}head->next = NULL;_size = 0;}bool isEmpty() {return _size == 0;}int size() {return _size;}void insert(int& e) {_size++;if (head->next == NULL) {head->next = new LNode(e);return;}LNode* p = new LNode(e);p->next = head->next;head->next = p;}void insert(int index, int a) {if (index < 1 || index > _size + 1) {return; // 无效的插入位置，直接返回}_size++;LNode* p = head;// 移动 p 到要插入位置的前一个节点for (int i = 1; i < index; i++) {p = p->next;}LNode* tmp = new LNode(a);tmp->next = p->next;p->next = tmp;}void print_L() {LNode* p = head->next;while (p != NULL){cout << p->data << " ";p = p->next;}cout << endl;}int change(){int x, y;cin >> x >> y;if (x<0 || x>_size || y<0 || y>_size){cout << "error" << endl;return -1;}if(x == y) return 0;LNode *pxprev = nullptr, *px = head, *pyprev= nullptr,*py=head;for (int i=0;i<x;i++){pxprev=px;px=pxprev -> next ;}for(int i=0;i<y;i++){pyprev=py ;py=pyprev -> next ;}pxprev -> next = px -> next ;pyprev -> next=px ;px -> next= py ;return 0;}
};
int main() {
List LB;int n, a;cin >> n;for (int i = 0; i < n; i++){cin >> a;LB.insert(i + 1, a);}LB.print_L();int t;cin >> t;for (int i = 0; i < t; i++){int result = LB.change();if (result == -1)continue;LB.print_L();}return 0;
}
“`
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