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Declaring (initializing) array without size

Oyvind Tjervaag

Hi!

I'm having some problems declearing an array. I am trying to make an array that contains messages that I will later display on an LCD display. I am using a 2D char array, but I don't want to specify a fixed size to the second dimension. At the moment i am doing this:

const char message[][20] = {
	"RS232 Monitor",
	"By: Oyvind Tjervaag",
	"V1.0",
};

The problem with this is that a lot of space is wasted scince there is only one string that fills up the 20 chars. Here the "V1.0" string will be the 4 chars I want to use followed by 16 0x00...

The annoying thing about this is that I have have done it before.. But I can't find the code where I did it...

I thought I could do it like this:

const char message[][] = {...}
But that is just giving me the error, "Too many initializers" , which of course means that I am trying to add more variables than what can fit into the array.

Could someone give me any hints about this?

Thanks
Øyvind

  • 0

    You are creating a 2-dimensional array. What you probably want is an array of pointers (to strings). For example:

    char *array [] =
  {
  "This",
  "is",
  "an",
  "array",
  "of",
  "pointers",
  "to",
  "strings.",
  };

    array[0] points to "this"
    array[1] points to "is"
    and so on.

    Jon

  • 0 in reply to Jon Ward

    Ahh... Yes, just tried it and that seems to be exactly what I need..

    Thanks Jon,

    Øyvind

  • 0

    Hi,

    Nice idea. I'm ew in embedded C and working on a nice project with a LCD. Therefore I'm writing a Hitachi 44780 module. It is workig perfect ut what I like to know is how to put a string to a LCD. The following a tried:

    /*
//  Write a string to the LCD *** Doesn't work at the moment *** Help needed!!!
*/
void LCD_String (char ROW, char COL, char *string)
{
	GoToXY (ROW, COL);
	while (*string)
		LCDdata (*string++);
}


    char lcdstr = "LCD Ready";
LCD_String(1,1,*lcdstr);

    If I try this, nothing apears on the LCD.

    "GoToXY" and "LCDdata" are working perfectly because I tried it seperatly.

    If I introduce the "LCD_String", No string on the LCD.

    Do I need to include some libraries?
    Or what else do I wrong?

  • 0 in reply to J.B. Schueler

    You have defined lcdstr to be a single char, whereas you need a string:

    Try either

    char * lcdstr = "LCD Ready";
    Or,
    char lcdstr [] = "LCD Ready";
    and then lose the '*' in the function call

  • 0 in reply to Andrew Neil

    Thanks for the fast reply.

    But.... neither functions seems to work.
    The first one come through the compiler but no string on the LCD. Infact, same result as I allready had.

    The other seems to bother the compiler.
    I get an error message error: need array size

    So.... I got dont know what to do....

  • 0 in reply to J.B. Schueler

    Is this what you ended up with?
    (This works fine for me.)

    void LCD_String (char ROW, char COL, char *string)
{
	GoToXY (ROW, COL);
	while (*string)
		LCDdata (*string++);
}



char lcdstr[] = "LCD Ready";
LCD_String(1,1,lcdstr);