How to extract numbers from string in c?

Question

Say I have a string like ab234cid*(s349*(20kd and I want to extract all the numbers 234, 349, 20, what should I do ?

Answer 1

You can do it with strtol, like this:

char *str = "ab234cid*(s349*(20kd", *p = str;
while (*p) { // While there are more characters to process...
    if ( isdigit(*p) || ( (*p=='-'||*p=='+') && isdigit(*(p+1)) )) {
        // Found a number
        long val = strtol(p, &p, 10); // Read number
        printf("%ld\n", val); // and print it.
    } else {
        // Otherwise, move on to the next character.
        p++;
    }
}

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