Question

我正在学习一个非常简单的链表，
但是下面这段代码不起作用，当我输入1和2时，系统输出只有1而且是NULL 有人可以帮帮我吗？这是我的代码。

#include <iostream>  

using namespace std;  

struct node  
{  
    char username[10];  

    node *next;  
};  



int main()  
{  
    node *head;  
    node *place;  
    node *tail;  

    head = new node;  
    place = head;  
    tail = place->next;  

    cout<<"username 1 ";  
    cin>>place->username;  
    place = tail;  
    place = new node;  
    tail = place->next;  
    cout<<"username 2 ";  
    cin>>place->username;  

    place = head;  
    cout<<"username 1 ";  
    cout<<place->username<<endl;  
    place = place->next;  
    cout<<"username 2 ";  
    cout<<place->username<<endl;  


    return 17;  
}

感谢您的任何帮助，谢谢。

Answer 1

您永远不会将节点链接在一起。在整个程序中没有任何地方设置 next 字段。在纸上解决这个问题，一次一个声明。而不是......

place = new node;  
tail = place->next;

创建新节点时，将其添加到列表末尾：将当前节点链接到新节点，然后移动结束指针。

place = new node;  
tail->next = place;
tail = place;

Answer 2

#include <iostream>  

using namespace std;  

struct node  
{  
    char username[10];  

    node *next;  
};  



int main()  
{  
    node *head;  
    node *place;  
    node *tail; 

    place = new node;  
    head = place;      // head is assigned to the first created place and should never be modified ever after.
    tail = head;      // at the beginning the last element is also the first, it will move along and always point to the last node created



    cout<<"username 1 ";  
    cin>>place->username;


    place = new node;    // create new node
    tail->next = place;  // assign next
    tail = place;        // then point the tail to the new node

    cout<<"username 2 ";  
    cin>>place->username;  

    place = head;      // rewind the list to the head
    cout<<"username 1 ";  
    cout<<place->username<<endl;  
    place = place->next;  
    cout<<"username 2 ";  
    cout<<place->username<<endl;  


    return 17;  
}

C ++，学习链表

2 个答案: