How to split a text file using tab space in c?

Question

I am doing a socket programming for that I having the following details in the text file. I want to split that text file using tab space and I need to assign them to the variabl

Answer 1

You can implement a simplistic parser with sscanf() or strtok() but be aware that neither of these will handle empty fields correctly. scanf's %[^\t] conversion specifier will fail if there are no characters before the next tab, and strtok() will consider any sequence of tabs a single delimiter.

Here is a solution with an ad hoc utility function that behaves similarly to strtok() but without its shortcomings:

#include 
#include 

char *getfield(char **pp, char sep) {
    char *p, *res;
    for (res = p = *pp;; p++) {
        if (*p == sep) {
            *p++ = '\0';
            *pp = p;
            return res;
        }
        if (*p == '\0')
            return NULL;
    }
}

int main() {
    char line[256];
    char filename[] = "input_file.txt";
    int lineno = 0;
    FILE *fp = fopen(filename, "r");
    if (fp != NULL) {
        while (fgets(line, sizeof line, fp)) {
            char *p = line;
            char *reference = getfield(&p, '\t');
            char *description = getfield(&p, '\t');
            char *quantity = getfield(&p, '\t');
            char *price = strtod(getfield(&p, '\n');
            lineno++;
            if (price != NULL) {
                /* all fields were parsed correctly */
                printf("reference: %s\n, reference);
                printf("description: %s\n, description);
                printf("quantity: %d\n, atoi(quantity));
                printf("price: %.2f\n\n, strtod(price, NULL));
            } else {
                fprintf(stderr, "%s:%d: invalid line\n", filename, lineno);
            }
        }
        fclose(fp);
    }
    return 0;
}