CODEWITHSUNDEEP
cstringscanfdelimiter
Stephen Burns
Stephen Burns

Reputation: 172

Can I set non-alphabetic characters as a delimeter in c when using fscanf?

I'm trying to read strings from a file using

while(fscanf(fd, "%s ", word) != EOF) {}

Where fd is the file and word is where I'm storing the string. However, this effectively uses the whitespace as the delimeter. Currently, if I have a file that reads "this% is, the4 str%ng" it would result in strings "this%", "is,", "the4", and "str%ng". I need it to be "this" "is" "the" "str" "ng". Is it possible to do this with fscanf, or is there something else I need to use?

I saw some answers here and here but they didn't seem to help me out.

Upvotes: 0

Views: 283

Answers (2)

Weather Vane
Weather Vane

Reputation: 34575

Those answers show the use of the "%[] format specifier. As an example suppose you have this to get two strings from the console:

#include <stdio.h>

int main(void){
    char s1[100] = "", s2[100] = "";
    int res;

    res = scanf("%99[^%]%%%99[^%]%%", s1, s2);
    printf("%d %s %s\n", res, s1, s2);
}

The first % starts the each format spec, the ^% tells scanf to stop at %, and the next "escaped" double % tells scanf to read the % that stopped the scan. It then repeats for the second string, so the format spec for one string is %99[^%]%% .

To make the format look simpler, suppose the delimiter is not % but #, then the code would be:

#include <stdio.h>

int main(void){
    char s1[100] = "", s2[100] = "";
    int res;

    res = scanf("%99[^#]#%99[^#]#", s1, s2);
    printf("%d %s %s\n", res, s1, s2);
}

The function fscanf is similar.

EDIT

This answer does not handle "unknown" delimiters, so I modified the code. 

#include <stdio.h>

int main(void){
    char s1[100] = "";
    while(scanf("%99[^!£$%&*()_-+={};:'@#~,.<>/?0123456789]", s1) == 1) {
        getchar();                      // remove the delimiter
        printf("%s\n", s1);
    }
}

Note I have not included characters ^ or " or [ or ] as delimiters.

Upvotes: 4

Afshin
Afshin

Reputation: 9173

If you don't have a specific delimiter (it seems to be your case), you need to parse each file line manually. You can read each line with fgets(), then parse manually(for example ignore every non-alphabetic chars).

Regards

Upvotes: 1

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