CString wrote as an unsigned char - vc90

Question

I am building an application to read and write to a microchip`s memory.
I need to pass an unsigned char array that has 4 fixed bytes and 2 variable bytes so suposing I want to read memory bank 0004 I will pass
unsigned char sRequest[32]={0};
sRequest[0] = 0x02; //FIXED
sRequest[1] = 0x1F; //FIXED
sRequest[2] = 0x0A; //FIXED
sRequest[3] = 0x20; //FIXED
sRequest[4] = 0x00; //VARIABLE
sRequest[5] = 0x04; //VARIABLE
I want to put 2 CEdit boxes for the user to input that variable memory bank, so it would write 0x00 on first CEdit and 0x04 on second one.
so my question is, how can I translate eacho of these inputs on an unsigned char so I can set it on my sRequest variable?
thanks in advance
(thanks dave, mistyped bytes into bits, fixed now)

Answer 1

Actually, I wouldn't do that with free-form text entry at all - it would be too much of a bother to do validation (being inherently lazy). If there's a chance to restrict what your user is able to give you as early as possible, you should take it :-)
I would provide drop-down boxes for the values, each nybble so that the quantity to select from is not too onerous. Something like (and with apologies for my graphical skills):
+---+-+ +---+-+ +---+-+ +---+-+
Enter value 0x | 0 |V| | 0 |V| | 0 |V| | 4 |V|
+---+-+ +---+-+ +---+-+ +---+-+
|>0<|
| 1 |
| 1 |
| 2 |
| 3 |
: : :
| E |
| F |
+---+
For the values in the listbox, I would set the item data to be 0 through 15 inclusive (for the items 0 through F).
That way, you could get a single byte value with something like:
byte04 = listboxA.GetItemData(listboxA.GetCurSel()) * 16 +
listboxB.GetItemData(listboxB.GetCurSel());
byte05 = listboxC.GetItemData(listboxC.GetCurSel()) * 16 +
listboxD.GetItemData(listboxD.GetCurSel());
If you must use a less restrictive input method, C++ provides:
int stoi (const string& str, size_t *idx = 0, int base = 10);
(and stol/stoul for signed and unsigned longs) to allow you to convert C++ strings to integral types.
For your purposes. you'll probably have to detect and strip a leading 0x (along with possibly leading/trailing spaces and so forth) which is why I suggest the restrictive route as a better option.