c++ - 使用链表插入排序的段错误

Question

我已经在这个项目上工作了一段时间，现在已经完全完成了。除了当我在 Linux 中运行它时出现段错误。我是 C++ 的初学者，虽然我知道段错误与尝试访问已释放的内存有关，但我不明白我尝试访问的内存哪里出了问题。以下是我遇到问题的功能。我用注释标记了我认为导致问题的代码行。如果您发现我做错了什么，请告诉我，我将不胜感激!

int TsuPod::SortSongList(string x, string y, int z)
{
    Song InsertSong(x, y, z); //creates song object

    node* newNode = new node; //creates new node

    //initializes all the node's values
    newNode->title = InsertSong.GetTitle();
    newNode->artist = InsertSong.GetArtist();
    newNode->size = InsertSong.GetSize();

    //case 1 - Inserting into an empty list
    if(head == NULL)
    {
        head = newNode;
    }
    else
    {
        curr = head;
    prev = NULL;

    //Traverse
    while(curr != NULL)
    {
            if(curr->title >= newNode->title)
        {
            break;
        }
        else
        {
            prev = curr;
            curr = curr->next;
        }
        }
    }   

    if(curr == head)
    {
    //case 2 - Insert at head
    newNode->next = head;
    head = newNode;       //Causing Segmentation fault?
    }
    else
    {
    //case 3 - Insert after the head
    newNode->next = curr;
    prev->next = newNode;
    }

    remainingMem = remainingMem - newNode->size;
    slots++;
    return 1;
}

Answer 1

首先让我印象深刻的是:

if(head == NULL)     <--- lets assume that head was null
{
    head = newNode;  <---- executed
}

else
{                    <---- not executed, skipped
    curr = head;     <---- this is skipped, curr is not assigned to head
    prev = NULL;

    //Traverse
    while(curr != NULL) { ... }
}  

if(curr == head)    <----- Huh... What is curr right now? When was 
                           curr last set to a value 
{ ... }

我并不是说段错误是由此引起的，我只是说这段代码有问题。