如何使用fscanf将任何字符读入字符串，直到到达选项卡？

Question

How to use fscanf to reads any character into a string until a tab is reached?

My data file have only 1 row:

123'\t'(Tab)345'\t'Le Duc Huy'\t'567

and i use fscanf like this:

fscanf(fin,"%d %d %d %[^\t]%s %d",&m,&n,&k,s,&q);

it return q with wrong value. Anybody can tell me what made it failed?

Answer 1

Using fscanf() , you will need a negated character class and a length:

char string[32];

if (fscanf(fp, "%31[^\t]", string) != 1)
    ...error or EOF...

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The modified version of the question has a data string with a single quote after the final tab, and the single quote cannot be converted to an integer, so the value in q is undefined. Note that you must check the return value of fscanf() to ensure that all the fields you expected to match actually did match, In the context, if probably returned the value 4 instead of 5, telling you there was an error.

Answer 2

Instead of fscanf I would just use fgetc (though my syntax may be off a bit):

int c;
string s = "";
for (;;)
{
    c = fgetc(somefile);
    if (c == '\t' || c == EOF) break;
    s += c;
    // ...
}

Answer 3

这是fscanf()版本：

fscanf (stream, "[^\t]", output);

Answer 4

Note, this is not safe!

char foo[100];
scanf("%s\t", foo);

You have no way of keeping the user from overflowing the buffer

Answer 5

Eliminate the space before %[ . It's eating your tab. Also, as others have said, this code is unsafe and probably unreliable on input that's not formatted exactly as you expect. It would be better to use fgets and then parse it yourself with strtol and a few for loops.