Question

How can I convert a hex ip (such as 42477f35), and get it to spit out the correct decimal ip (in the example before, the correct result is 66.71.127.53)?

I’d like it to take the hex ip in as a string, then output the correct result as a string too so I can use it elsewhere in the C code.

I’m not an expert in C, so if any of you can help me out, it’d be appreciated.

Answer 1

This is one possibility:

#include <stdio.h>

int ip_hex_to_dquad(const char *input, char *output, size_t outlen)
{
    unsigned int a, b, c, d;

    if (sscanf(input, "%2x%2x%2x%2x", &a, &b, &c, &d) != 4)
        return -1;

    snprintf(output, outlen, "%u.%u.%u.%u", a, b, c, d);
    return 0;
}