Question

How to check if a string contains only letters, numbers, underscores and dashes in C

Answer 1

#include <stdio.h>
#include <stdbool.h>
#include <regex.h>

bool isValidString(const char *s) {
    regex_t regex;
    int result;

    result = regcomp(&regex, "^[A-Za-z0-9_-]*$", REG_EXTENDED);
    if (result) {
        fprintf(stderr, "Could not compile regex\n");
        return false;
    }

    result = regexec(&regex, s, 0, NULL, 0);
    regfree(&regex);

    return result == 0;
}

int main() {
    const char *s1 = "-abc_123-";
    printf("%s\n", isValidString(s1) ? "yes" : "no");

    const char *s2 = "-abc_123-(!)";
    printf("%s\n", isValidString(s2) ? "yes" : "no");

    return 0;
}



/*
run:

yes
no

*/

 

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