Hello,

I am a C programming newbie. This is my first program and I have made it through quite well, researching tutorials on the web etc. I have a hurdle I just cannot figure out;

Code:
int main()
{
 /* Ask for a position input */
 bool ValueOk = false;
 unsigned char Posn[4] = {0};
 unsigned char Temp[1] = {0};
 long double a;
 long b;
 int i;
 int ulIdx;

 do
 {
  cout << "Enter Desired Position (0.00 -> 195.00 mm):  ";
  scanf("%Lf", &a);
  if (a >=0.00 && a<= 195.00)
  {
   if (a < 0)
   {
    b = floor(a * 100);
   } else
   {
    b = ceil(a * 100);
   }
   printf("%02X", b);
   Posn[0] = b;        <---- PROBLEM
   printf("%02X", Posn[0]);
   /* Invert Order Of Bytes For abSendData */
   for (ulIdx = 0; ulIdx < 4; ++ulIdx)
   {
    Temp[ulIdx + (3 - ulIdx)] = Posn[ulIdx];
   }
   for (i=0; i<4; ++i)
   {
    Posn[i] = Temp[i];
   }
   ValueOk = true;
  }
 } while (!ValueOk);
}
How do I copy the variable "b" (long), represented as (4) byte values, into the Posn[0, 1, 2, 3] array? I also, want to invert the order, hence the reason for the loop above. I want to then shuffle the (4) bytes in the Posn array, as Posn[3, 2, 1, 0]. How is this done? I've been playing with sprintf, without success. Would someone be kind enough to explain this to me?

Many thanks!