Thread: Incrementing array names

Hello guys,

Sorryto interrupt, but I have a problem what is driving me nuts.
First of all, I have some programming background, but I am not a professional.
I learned C & C++ just by doing and informing myself. Not classes visited in college whatsoever.

So, I try to program a Atmel microcontroller using WINAVR libs and wxDevC++ (GCC compiler based).
In my coding, I have a function:


->

Code:

void partPicTransfer(volatile uint16_t startAddress,
                                     volatile uint8_t xSize,
                                     volatile uint16_t picSize,
                                     const uint8_t picture[]);

As you can see, "const uint8_t picture[]" is a unsigned int array of variable size.
While I go through the code, at one point I use a for loop and try to use global varibles to modify the array name in that function in order to get the right array at a given point.
Example:

-> Array I try to access:

Code:

const uint8_t GBNum1[] PROGMEM = {.....};

-> Global variable:

Code:

unsigned int thr = 0;

-> Execution:

Code:

partPicTransfer(0x681, 4, 128, GBNum(thr));

"thr" is the value, which should increment the array name in the loop.
That way, I get of course linker problems, since GBNum is unknown.
So, how can I make the program to recognize my operation?

Again, sorry if this is annoying you, but I worked the last 3 hours on that and still am lacking some C background.
´
I would really appreciate it, if you could give me a hand here.
Greetings,

Thomas. (LFrieza)

Nope.
The compiler tells me that GBNum is undeclared, which is understandable, since the arraysnames are the ones I try to increment.

Array names I try to access that way (listup):

Code:

const uint8_t GBNum0[] PROGMEM = {.....}

to

const uint8_t GBNum9[] PROGMEM = {.....}

As you can see, I try actually to access the array named "GBNum0" - "GBNum9".
"thr" should therfore only increment the last part of the arrayname.

Thanks for the try though.

Greetings,
Thomas

Originally Posted by LFrieza

I learned C & C++ just by doing and informing myself.

I.e., the usual way.

You need a 2-dim array, like vart says. Or something like:

Code:

uint8_t **GBNum[9];
GBNum[0] = GBNum0;
...

Hello again,

thank you all very much for your help!
Finally, I got that problem out of my code...

Adding:

Code:

uint8_t *GBNumbers[10] = {GBNum0, GBNum1, GBNum2, GBNum3, GBNum4, GBNum5, GBNum6, GBNum7, GBNum8, GBNum9};

Using as follows:

Code:

      partPicTransfer(0x68C, 4, 128, GBNumbers[7]);
      partPicTransfer(0x68F, 4, 128, GBNumbers[0]);

Now I get to the information I wanted; thanks again for your time!
Hopefully, I will be able to help you also in the near future!

Have good nights,
Thomas