# Thread: String Manipulation / Juxtaposition

1. ## String Manipulation / Juxtaposition

Would someone be kind enough to help me with this seemingly simple (yet difficult for a non-C guy like me) problem...

Assuming buf contains a string similar to either one of these:

Code:
```50005112601012121148\n in buf
... or ...
600000112401092112156\n in buf```
How do I juxtapose/manipulate the numbers so that I end up with the following:

Code:
```010.112.148.212 in ip, and 5000 in port.
... or ...
010.112.156.211 in ip, and 60000 in port.```
The logical formula for the decode is as follows (from right to left):
- last three bytes of string are the third IP octet.
- prior byte is junk, and can be anything. Ignore.
- prior three bytes of string are the fourth IP octet.
- prior byte is junk, and can be anything. Ignore.
- prior three bytes of string are the first IP octet.
- prior byte is junk, and can be anything. Ignore.
- prior three bytes of string are the second IP octet.
- prior byte is junk, and can be anything. Ignore.
- prior bytes (might be 4 or 5 in length) are the port.

I can do it in a relatively straightforward way, assuming the string is always the same length. But I don't know an easy way of doing this with a string that might vary in size. Here's how I'm doing it, but of course it doesn't work for the shorter (first example) string...
Code:
```    f = buf;
*(f + 5) = '\0';

servers[x].port = atoi(f);
f += 6;

*(f + 3) = '\0';
*(f + 7) = '\0';
*(f + 11) = '\0';

if (*(f + 4) == '0')
strcpy(servers[x].ip, (f + 5));
else
strcpy(servers[x].ip, (f + 4));

strcat(servers[x].ip, ".");
strcat(servers[x].ip, (f + 0));
strcat(servers[x].ip, ".");
strcat(servers[x].ip, (f + 12));
strcat(servers[x].ip, ".");
strcat(servers[x].ip, (f + 8));```
Help (in the form of some code) would be greatly appreciated at this time... my mind is melting.