从给定的LinkedList在C ++中创建一个反向LinkedList [英] Create a reverse LinkedList in C++ from a given LinkedList

问题描述

我来自一个java背景，刚刚开始做一些C ++。 / p>

你可以查看我的代码，看看有什么问题吗？

  //这是一个linkedlist类的方法，它创建一个反向linkedlist 
 //并打印它
 
 void LinkedList :: reversedLinkedList（）
 {
 Node * revHead; 
 
 //检查常规列表是否为空
 if（head == NULL）
 return; 
 
 //否则开始反转
 node * current = head; 
 while（current！= NULL）
 {
 //检查是否是第一个添加的
 if（revHead == NULL）
 revHead = current; 
 
 else 
 {
 //刚刚在开头插入
 Node * tempHead = revHead; 
 current-> next = tempHead; 
 revHead = current; 
} 
 current = current-> next; 
 
} // end while 
 
 //现在打印它
 cout< Reversed LinkedList：< endl; 
 
 Node * temp = revHead; 
 while（temp！= NULL）
 {
 cout< temp-> firstName<< endl; 
 cout<< temp-> lastName<< endl; 
 cout<< endl; 
 
 temp = temp-> next; 
} 
 
} //结束方法
  

解决方案

更容易：浏览您的链接列表，保存上一个和下一个节点，并让当前节点指向上一个节点：

  void LinkedList :: reversedLinkedList（）
 {
 if（head == NULL）return; 
 
节点* prev = NULL，* current = NULL，* next = NULL; 
 current = head; 
 while（current！= NULL）{
 next = current-> next; 
 current-> next = prev; 
 prev = current; 
 current = next; 
} 
 //现在让头点在最后一个节点（prev）
 head = prev; 
} 
  

I'm having some trouble create a linkedlist in reverse order from a given linkedlist.

I come from a java background, and just started doing some C++.

Can you check out my code and see what's wrong? I'm guessing I'm just manipulating pointer and not creating anything new.

//this is a method of linkedlist class, it creates a reverse linkedlist
//and prints it

void LinkedList::reversedLinkedList()
{
    Node* revHead;

    //check if the regular list is empty
    if(head == NULL)
       return;

    //else start reversing
    Node* current = head;
    while(current != NULL)
    {
        //check if it's the first one being added
        if(revHead == NULL)
           revHead = current;

        else
        {
            //just insert at the beginning
            Node* tempHead = revHead;
            current->next = tempHead;
            revHead = current;
        }
        current = current->next;

     }//end while

     //now print it
     cout << "Reversed LinkedList: " << endl;

     Node* temp = revHead;
     while(temp != NULL)
     {
         cout << temp->firstName << endl;
         cout << temp->lastName << endl;
         cout << endl;

         temp = temp->next;
      }

}//end method

解决方案

Easier one: Go through your linked list, save the previous and the next node and just let the current node point at the previous one:

void LinkedList::reversedLinkedList()
{
    if(head == NULL) return;

    Node *prev = NULL, *current = NULL, *next = NULL;
    current = head;
    while(current != NULL){
        next = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }
    // now let the head point at the last node (prev)
    head = prev;
}

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