单链表的中间节点

#include<iostream> using namespace std; struct ListNode{ int m; ListNode *next; }; ListNode *Creat () { ListNode *pHead = nullptr; ListNode *p1,*p2; p1 = new ListNode; cout<<"Please Enter a Number:"<<endl; cin>>p1->m; while(p1->m != 0) { if(pHead == nullptr) { pHead = p1; p2 = p1; } else { p2->next = p1; p2 = p1; } p1 = new ListNode; cout<<"Please Enter a Number:"<<endl; cin>>p1->m; } p2->next = nullptr; return pHead; } void print(ListNode *pHead) { ListNode *p = pHead; while(p != nullptr) { cout<< p->m<< "\t"; p = p->next; } cout<<endl; } ListNode *GetMiddleNode (ListNode *pHead) { if(pHead==nullptr) return nullptr; if(pHead->next==nullptr) return pHead; ListNode *pAhead = pHead; ListNode *pBehind = pHead; /***偶数个结点时，输出后面的***/ /*while(pAhead->next != nullptr) { pAhead = pAhead->next; pBehind = pBehind->next; if(pAhead->next != nullptr) pAhead = pAhead->next; }*/ /***偶数个结点时，输出前面的***/ while(pAhead->next!=nullptr&&pAhead->next->next!=nullptr) { pAhead = pAhead->next->next; pBehind = pBehind->next; } return pBehind; } int main () { ListNode *Head; Head = Creat(); cout<<"The ListNode is"<<endl; print(Head); ListNode *Middle; Middle = GetMiddleNode(Head); cout<<"The Middle Node is:"<<Middle->m<<endl; }