length of a string up to a specific character

Question

I want to search an IP address up to the "/" and take everything before the "/" so I can convert it from a char to an int. Then take that int and convert it to binary. How would I read everything before the "/", store it in a variable, and then continue to convert it to binary. I'm aware of strlen but don't think that will work with my situation? The length up to "/" is not constant.

My code:

 int main(int argc, char** argv)
 {
      char *s;
      char buf[] = "10.29.246.49/32";
      s = strchr(buf, '/');
      if (s != NULL)
           printf("found '/' at %s\n", s);
      return 0;
 }

Answer 1

You can use strtok

#include <stdio.h>
#include <string.h>
int main(int argc, char** argv)
{
      char *s;
      char buf[] = "10.29.246.49/32";
      s = strtok(buf, "/");
      if (s)
           printf("%s\n", s);
      return 0;
}

This program yields

10.29.246.49

The character '/' is replaced with '\\0' . Now you can use strlen on the string.