实现单链表逆置

 

 

看到笔试和面试里很多这样的题目，于是就练习一下，温故知新。

#include <iostream>

#include <cstdlib>

using namespace std;

typedef struct List

{

   int data;

   struct List *next;

}listNode,*pList;

void createList(pList & list)                   //头插入法建立单链表

{

     pList head=NULL;

     int data;

     cout<<"please input a node:";

     cin>>data;

     list=(struct List *)malloc(sizeof(listNode));

     list->data=data;

     list->next=head;

     head=list;

     while(data!=9)

{

     cout<<"please input a node:";

     cin>>data;

     list=(struct List*)malloc(sizeof(listNode));

     list->data=data;

     list->next=head;

     head=list;



}

} 

void display(pList list)                    //输出单链表

{

     pList temp;

     temp=list;

     while(temp!=NULL)

{

     if(temp->next==NULL)

     cout<<temp->data;

     else

     cout<<temp->data<<"->";

     temp=temp->next;

}

    cout<<endl;



}



void reverseList(pList& list)              //逆置单链表

{

    pList pre;

    pList temp;

    pre=list->next;                        //记录当前节点

    temp=pre->next;                         //记录下一个节点

    list->next=NULL;

    while(pre!=NULL)

{

    pre->next=list;

    list=pre;

    pre=temp;

    if(pre!=NULL)

    temp=temp->next;

     else

     break;   

}

   // pre->next=list;

   // list=pre;

}

int main()

{

    pList list=NULL;

    cout<<"create the list :"<<endl;

    createList(list);

    cout<<"output the list:"<<endl;

    display(list);

    cout<<endl;

    cout<<"reverse the List:"<<endl;

    reverseList(list);

    cout<<"output the reverse list:"<<endl;

    display(list);

    cout<<endl;

    return 0;

}

　　

上面逆置算法也可以这样写：

void reverseList(pList& list)             //逆置

{

    pList pre;

    pList temp;

    pre=list->next;                    //记录当前节点

    temp=pre->next;                    //记录下一个节点

    list->next=NULL;

    while(temp!=NULL)

{

    pre->next=list;

    list=pre;

    pre=temp;

    temp=temp->next;  

}

   pre->next=list;

   list=pre;

}

　　

截图：