Hi there,

I'm currently working on a new project where I have to use a binary tree which may become rather big. Therefore I need to keep the nodes themselves as small in size as possible. Quite frequently I have integer values which range only from 0 to 255, so they could be saved in 1 Byte. In original C, there is the "byte" type for that. However, it seems not to exist in lite-C according to the manual. Can I define a data-type which stores an integer value between 0 and 255 in 1 Byte of memory? If so, how do I do that?

EDIT: How about True/False-Values? Boolean values take only 1 bit to save. It would be a real waste to use even a "short" integer for that. Is there any more "economic way" to do this?

Thanks in advance,


Alan

char

I thought that character values (char) save letters only?

Letters are nothing else than a variable stored in 1 byte.

So I won't get any trouble because of type conversion if I write something like:

char a_var;

a_var = 180;


In some languages this DOES cause some serious trouble.


EDIT: And how about boolean values? Any chance to use only 1 Bit for them?

I don't know about other languages but in Lite-C or C/C++ this will work fine. There is no difference between a_var = 97; or a_var = 'a';

Ok, great then, thanks so far! Last question left is the thing about booleans. I really have a LOT (~15) boolean values in my struct. Is it possible to use a smaller var-type then "char" for them?

There is BOOL but AFAIK it actually needs more than 1 bit which makes it pretty useless if you want to save space. But you can use bits of a variable and use them as flags just like the engine does with its objects if you really need to save space:

#define FLAG1 (1<<0) // Replace FLAG1 etc. with meaningful names, these exact definitions are already in atypes.h
#define FLAG2 (1<<1)
#define FLAG3 (1<<2)
#define FLAG4 (1<<3)
#define FLAG5 (1<<4)
#define FLAG6 (1<<5)
#define FLAG7 (1<<6)
#define FLAG8 (1<<7)

...

long a_var;

...

a_var |= FLAG1; // set first bit/flag to 1
a_var &= ~FLAG1; // set first bit/flag to 0

Wohooo, bit-shifting, huh? Never got to actually USE this, I've only heard about it in university... impressive! Sounds like a good solution!

Thanks a LOT! You really helped me out!

you could use bitfields:

http://en.wikipedia.org/wiki/Bit_field

joey