void permute(char * input, char * next);
void remove(char * destination, char * source, int position);

void permute(char * input) {
   char buffer[] =  { 0 };
   permute(input,buffer);
}
void permute(char * input, char * next) {
   if (!input[0]) printf("%s\n",next);
   for (int i = 0; *(input+i); ++i) {
       char buff[128];
       char _buff[128];

       remove(buff,input,i);

       int len = strlen(next);

       memcpy(_buff,input+i,1);
       memcpy(_buff+1,next,len+1);

       permute(buff, _buff);
   }
}
void remove(char * output, char * input, int pos) {
   int length = strlen(input), posi = 0;
   for (int i = 0; i <= length; ++i)
       if (pos != i) output[posi++] = *(input+i);
}