c-写入具有嵌套结构的链表

Question

我正在尝试编写一个函数，该函数可以将文件中的一些信息读取到双链表中的节点中。每个节点数据的格式如下。

结构（命名记录）
艺术家
相册
歌曲
流派
songLength（这是另一个包含分钟和秒的结构）
播放次数
评级

void load(FILE *file, Node *head)
{
    char tempArtist='', tempAlbum='', tempTitle='', tempGenre=''
    ,tempSpace='',tempMins='',tempSecs='';
    SongLength *tempLength=NULL;
    int tempPlay=0, tempRating=0,test=0;
tempLength = (SongLength*)malloc(sizeof(SongLength));
    fscanf(file,"%s",&tempArtist);
    fscanf(file,"%s",&tempAlbum);
    fscanf(file,"%s",&tempTitle);
    fscanf(file,"%s",&tempGenre);
    fscanf(file,"%s",&tempMins);
    fscanf(file,"%s",&tempSecs);
    fscanf(file,"%s",&tempPlay);
    fscanf(file,"%s",&tempRating);
    fscanf(file,"%s",&tempSpace);
    tempLength->mins=tempMins; 
    tempLength->secs=tempSecs;
    head->data->album=tempAlbum; // breaks here
    head->data->artist=tempArtist;
    head->data->genre=tempGenre;
    head->data->song=tempTitle;
    head->data->length=tempLength;
    head->data->played=tempPlay;
    head->data->rating=tempRating;
}

这是我当前的负载函数。当试图将这些值存储到节点数据中时，我会遇到访问冲突。

以下是我的结构，便于复制

typedef struct songlength
{
    int mins;
    int secs;
}SongLength;

typedef struct record
{
    char artist;
    char album;
    char song;
    char genre;
    struct songlength *length;
    int played;
    int rating;
}Record;
typedef struct node
{
    struct node *pPrev;
    struct node *pNext;
    struct record *data;
}Node;

---

makeNode

Node *makeNode(Record *newData)
{
    Node *temp = NULL;
    temp=(Node*)malloc(sizeof(Node));
    temp->data=newData;
    temp->pNext=NULL;
    return temp;
}

如果有任何困惑，请告诉我！这也是我第一次体验动态记忆，所以要温柔：P

谢谢！

Answer 1

这些行不正确。

fscanf(file,"%s",&tempArtist);
fscanf(file,"%s",&tempAlbum);
fscanf(file,"%s",&tempTitle);
fscanf(file,"%s",&tempGenre);
fscanf(file,"%s",&tempMins);
fscanf(file,"%s",&tempSecs);
fscanf(file,"%s",&tempPlay);
fscanf(file,"%s",&tempRating);
fscanf(file,"%s",&tempSpace);

由于变量的定义方式，它们肯定会导致未定义的行为。

你不能指望

char c = '';
fscanf(file, "%s", &c);

工作。&c的内存不足，无法读取字符串。你需要这样的东西：

char s[100]; // Or some size that is large enough to hold the data
             // you are about to read.
fscanf(file, "%99s", s); // Make sure that you don't read more than 99
                         // characters. Leave at least one character
                         // for the terminating null character.

我希望这能给你足够的线索来改变你的变量。

Answer 2

您没有为要指向的变量tempLength分配内存。

在访问元素之前添加此项

SongLength *tempLength = malloc(sizeof(struct(SongLength));

编辑

我只是给出了一个如何为您的案例分配和使用嵌套结构的总体想法

Node *head;
Record *r=malloc(sizeof(struct record));
SongLength *s=malloc(sizeof(struct songlength));
r->length=s;//<----- 1
r->length->mins=10;//Now you can assign values
head=malloc(sizeof(struct node));
head->pPrev=NULL;
head->pNext=NULL;
head->data=r;//<--- The length member inside record is already assigned memory in 1
head->data->artist='c';
head->data->length->mins=10;//assign