xor encode buffer in c

[noeska]

First of all i know this is not the forum to ask c questions.
So if you know better places where i can ask this question do let me know.

The idea is that i get an pointer to data what i want to xor encode with an password.
I propably should cast the pointer or something like that to get things to work.
But for the moment i am out of ideas.

building:

void XorEncode(void *password, void *data) 
{ 
   int dlength = length(data); 
   int ipl = length(password); 
   int ip = 0; 
   int i =0; 
   for &#40;i=0; i < dlength; i++&#41; &#123; 
              if &#40;ip = ipl&#41; ip = 0; 
            data&#91;i&#93; = data&#91;i&#93; ^ password&#91;ip&#93; ;  //this is line 29 
            ip +=1; 
   &#125; 

&#125;

gives the following error:

Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland 
crypt.c: 
Error E2453 crypt.c 29: Size of the type 'void' is unknown or zero in function X 
orEncode 
Error E2109 crypt.c 29: Not an allowed type in function XorEncode 
Error E2453 crypt.c 29: Size of the type 'void' is unknown or zero in function X 
orEncode 
Error E2109 crypt.c 29: Not an allowed type in function XorEncode 
Error E2453 crypt.c 29: Size of the type 'void' is unknown or zero in function X 
orEncode 
Error E2109 crypt.c 29: Not an allowed type in function XorEncode 
*** 6 errors in Compile *** 

** error 1 ** deleting crypt.obj

Thanks for your answers in advance.