链表的partition

#include <iostream>#include <string>using namespace std;class Node {private:   int item;   Node *next;public:   Node();   Node(int value);   Node *getNext() const;   void setNext(Node * nextPtr);   int getItem() const;   void setItem(int value);};Node::Node():item(0),next(nullptr){}Node::Node(int value):item(value),next(nullptr){}Node * Node::getNext() const{   return next;}void Node::setNext(Node * nextPtr){   next = nextPtr;}int Node::getItem() const{   return item;}void Node::setItem(int value){   item = value;}Node * partition(Node * headPtr,int x){   Node * beforStart = nullptr;   Node * afterStart = nullptr;   while(headPtr != nullptr)   {      Node * nextNodePtr = headPtr->getNext();      if(headPtr->getItem() < x)      {         headPtr->setNext(beforStart);         beforStart = headPtr;      }      else      {         headPtr->setNext(afterStart);         afterStart = headPtr;      }      headPtr = nextNodePtr;   }   if(beforStart == nullptr)      return afterStart;   Node * head = beforStart;   while(head->getNext() != nullptr)      head = head->getNext();   head->setNext(afterStart);   return beforStart;  }void printNodeChain(Node * headPtr){while(headPtr != nullptr){cout<<headPtr->getItem()<<" ";headPtr = headPtr->getNext();}cout<<endl;}int main(){int arr[6] = {3,8,9,1,2,4};Node * headPtr = nullptr;for(int i = 0; i < 6; i++){Node * nodePtr = new Node();nodePtr->setItem(arr[i]);nodePtr->setNext(headPtr);headPtr = nodePtr;}printNodeChain(headPtr);headPtr = partition(headPtr,5);printNodeChain(headPtr);return 0;}