C Programming. Convert string www.as.com to 3www2as3com0

Question

please can you give me some ideas to convert a string such as: char string[20]="www.msn.es" to another string : 3www3msn2es0 . I just want ideas please, should I use strstr or you just can do it with char pointer and bucles. Thanks so much, it's my first time in this forum.

Answer 1

This works for me (note that it assumes the length of each segment in the hostname will be 9 chars or less, though):

#include <stdio.h>
#include <string.h>

int main(int argc, char ** argv)
{
   if (argc < 2)
   {
      printf("Usage:  ./rr www.msn.es\n");
      return 10;
   }

   char outbuf[256] = "\0";
   const char * in = argv[1];
   char * out = outbuf;
   while(*in)
   {
      const char * nextDot = strchr(in, '.');
      if (nextDot == NULL) nextDot = strchr(in, '\0');
      *out++ = (nextDot-in)+'0';
      strncpy(out, in, nextDot-in);
      out += (nextDot-in);
      if (*nextDot == '\0') break;
                       else in = nextDot+1;
   }
   *out++ = '0';
   *out++ = '\0';
   printf("%s\n", outbuf);

   return 0;
}