quote:Original post by deadlydog
I don't understand it because it starts to say that I'm missing an ';' somewhere before I declare the const int blah, even though I haven't changed anything else.

Any solutions?? Thnx guys again.

I dug up the file you used from Tricks, demo7_13, and changed that one line. The program worked. I have a suggestion: make a new project workspace and start over with the original file found on the cd, and change that one line again. It should work if you only change that one line.

EDIT: okay, I didn't actually run the program, I just meant it compiled fine. When I did run it, I found that that was the program that refused to work on my computer properly.(ie, crap showed up on the screen) But anyway, the program should compile properly.

[edited by - nobodynews on December 7, 2002 2:15:37 PM]

quote:Original post by RuneLancer
And if you want to be clever, I don''t think you can use the C++ "const" to do something like...

#declare Begin {
#declare End }

(or something to that end). Teehee.

No, you certainly can''t. I''m not sure I''d consider that particularly clever, though ... if you really want Begin ... End blocks, use Pascal or something. One potential pitfall of clever tricks (though it doesn''t apply here) is the possibility of having your clever #define clash with a variable name and get all sorts of unpredictable replacements (if you''re not careful).

But in any case, I shan''t deny that there may be cases where #defines are preferable to const variables (as I said in my first post, consts are usually better than #defines; I never said ''always''); I just can''t think of any, and in simple cases (as here), I''d recommend the const variable.

As has been said many times, #define is a dumb replacement of text.

believe it or not, thats an understatement. It is extremely literal.

Given this

#define SCREEN_WIDTH = 640

every time it sees "SCREEN_WIDTH", that gets replaced with "= 640", that can really screw up your code. When using #define DO NOT USE an "=" because it takes everything after it.

#define can do some really nice stuff if used properly, if not it can create havoc.

Take Squaring a number for example:
Correct:
#define SquareIt(n) ((n)*(n))
Wrong:
#define SquareIt(n) n*n
Given " X * SquareIt(Y + Z)/W;" It translates to "X * Y + Z*Y + Z/W"
#define SquareIt(n) ((n)*(n));
Given " X * SquareIt(Y + Z)/W;" It translates to "X * ((Y + Z)*(Y + Z));/W;"

And the #define''s work top down, so they can mess each other up if your not careful. Any time you use a #define, it should be well thought out, and clear as day to how your using it.

TIP:
Put all your defines in one place so they are easy to find, and reference. #pragma once ontop of all your files can help if you have a complicated project.


Compiling...
demo7_13.cpp
D:\My Documents\C++ Files\Source\T3DCHAP07\demo7_13.cpp(33) : warning C4091: '' : ignored on left of ''const int'' when no variable is declared
D:\My Documents\C++ Files\Source\T3DCHAP07\demo7_13.cpp(33) : error C2143: syntax error : missing '';'' before ''constant''
D:\My Documents\C++ Files\Source\T3DCHAP07\demo7_13.cpp(33) : fatal error C1004: unexpected end of file found
Error executing cl.exe

Given the second 2 errors, you may have a problem further up the line as well...Try formatting your code and looking for a missing }.