#define array index not working

Question

I'm trying to #define a constant at the top of the header file and use that value as the index size of my arrays. I'm getting the following error:

Error C2059: syntax error : ']'

I'm curious as to why?

#define MAX_TEAMS = 20; class Program { public: int atk_val[MAX_TEAMS]; // Error! int atk_val[20]; // Works! }

please note that you should better use a static const as Captiain Obvlious pointed out, or even better use standard containers instead of plain arrays — 463035818_is_not_an_ai
– 463035818_is_not_an_ai, Commented Jul 10, 2015 at 11:19
and btw you are defining the size of the array and not its index. (yes sometimes I like hairsplitting). If your program has no bugs, the index should never reach this value ;) — 463035818_is_not_an_ai
– 463035818_is_not_an_ai, Commented Jul 10, 2015 at 11:21

Mohit Jain · Accepted Answer · 2015-07-10 11:16:25Z

Replace #define MAX_TEAMS = 20; with

#define MAX_TEAMS 20

In current form the code int atk_val[MAX_TEAMS]; will be expanded to

int atk_val[= 20;]; // ^ ^

And thus the error message seen by you.

Always remember that MACROs are not variables.

463035818_is_not_an_ai · Accepted Answer · 2015-07-10 11:16:31Z

When you define the symbol in this way:

#define MAX_TEAMS = 20;

you define MAX_TEAMS to be replaced with = 20;

Ed Heal · Accepted Answer · 2015-07-10 11:16:42Z

1

Change

 #define MAX_TEAMS = 20;

to

#define MAX_TEAMS 20

#define does a string substitution.

answered Jul 10, 2015 at 11:16

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1 Comment

Please see the comment above - it is a better solution to mine in the C++ world.