c - 将文本文件中的一行读取到c中的字符数组中

Question

我正在尝试从文本文件填充数组。该数组位于以下结构中:

struct ISBN
{
    long value;
};
struct Author
{ 
    char authorName[60];
};
struct  Book
{
    char *bookTitle;
    struct Author bookAuthor;
    struct ISBN bookID;
};

我尝试编写一个填充函数，它接受 Book 类型的文件和结构，如下所示:

void fillin (FILE * file, struct Book * bk)
{
    bk->bookTitle =(char*) malloc(1000);
    size_t n = 0;
    int c;

    file=fopen("book.txt","r");

    while ((c = fgetc(file)) != '\n')
    {
        bk->bookTitle[n++] = (char) c;
    }

    bk->bookTitle[n] = '\0'; 

    fscanf(file,"%s", &bk->bookAuthor.authorName);
    fscanf(file,"%lld",&bk->bookID.value);

    //fscanf(file,"%s", &bk->bookTitle);
}

文件 book.txt 包含以下数据:

UNIX Network Programming
W. Richard Stevens
0131411551

问题是，它无法扫描数组，我想从文本文件中填充 bookTitle 和 autherName 数组。

Answer 1

以下行是错误的:

fscanf(file,"%s", &bk->bookAuthor.authorName);

当你扫描一个字符串时，字符数组已经是一个指针，所以你不需要获取它的地址(&)。尝试:

fscanf(file,"%s", bk->bookAuthor.authorName);

为了安全(在长字符串的情况下)，您可以使用此函数:

char * fgets ( char * str, int num, FILE * stream );

因此:

fgets(bk->bookAuthor.authorName, 60, file);

如果该行太长，则字符串的其余部分将不会被复制进来。如果这样做，您可能必须检查字符串是否尚未终止，并丢弃其余的字符，直到换行符。 (例如，while ((c = fgetc(file)) != '\n');)。\n 字符被复制进来，因此您必须找到并删除它:

bk->bookAuthor.authorName[59] = 0; // make sure it is null-terminated
int last = strlen(bk->bookAuthor.authorName)-1;
if (bk->bookAuthor.authorName[last] == '\n') {
    bk->bookAuthor.authorName[last] = 0; // read whole line
}
else ; // terminated early

您还可以使用 fscanf 限制字符，并使用以下方法读取空格:

char c;
scanf(file, "%60[^\n]%c", bk->bookAuthor.authorName, c);

if (c=='\n') {
    // we read the whole line
} else {
    // terminated early, c is the next character
    //if there are more characters, they are still in the buffer
}

要放弃该行的其余部分，您可以执行类似的操作

while (c != '\n' && c != EOF) c = fgetc(file);