c - 在 fscanf() 中使用 []

Question

我有一个包含以下内容的文本文件:

"abc","def","ghi"

以下工作可以正确读取文件内容:

int main()
{
    char name[1024] = {0};
    FILE *file = fopen("file.txt", "r");

    while(1)
    {
        if (fscanf(file, " %[\",]s ", name) == EOF)
            break;
        if (fscanf(file, " %[a-zA-Z]s ", name) == EOF)
            break;

        printf("%s\n", name);
    }

    return 0;
}

但是，以下操作失败了:

int main()
{
    char name[1024] = {0}, garbage[5];
    FILE *file = fopen("file.txt", "r");

    while(1)
    {
        if (fscanf(file, " %[\",]s%[a-zA-Z]s ", garbage, name) == EOF)
            break;

        printf("%s\n", name);
    }

    return 0;
}

我正在使用 MSVC++ 08。我缺少什么？我正在寻找在 while 循环中使用单个 fscanf() 的解决方案。

Answer 1

有用吗？？？纯粹的倒霉:-)

您的转换规范意味着

" %[\",]s "
         ^= optionally skip whitespace
        ^== read a literal 's'
  ^^^^^^=== read an unlimited string of quotes and commas
 ^========= optionally skip whitespace

和

" %[a-zA-Z]s "
            ^= optionally skip whitespace
           ^== read a literal 's'
  ^^^^^^^^^=== read an unlimited string of letters
 ^============ optionally skip whitespace

和

" %[\",]s%[a-zA-Z]s "
                   ^= optionally skip whitespace
                  ^== read a literal 's'
         ^^^^^^^^^=== read an unlimited string of letters
        ^============ read a literal 's'
  ^^^^^^============= read an unlimited string of quotes and commas
 ^=================== optionally skip whitespace

我觉得你想要

" %4[\",]%1023[a-zA-Z] "
                      ^= optionally skip whitespace
         ^^^^^^^^^^^^^== read a string of at most 1023 letters
  ^^^^^^^=============== read a string of at most 4 quotes and commas
 ^====================== optionally skip whitespace

---

除此之外，scanf 返回成功转换的次数或出错时返回 EOF。当您应该与 1(或 2，或其他)进行比较时，您正在将结果值与 EOF 进行比较:与您期望的转化次数进行比较。

if (scanf() == 3) /* expected 3 conversions */
{ /* ok */ }
else { /* oops, something went wrong */ }