global variables and multidimensional arrays

[LowLife]

Hi, can someone please tell me why I cant define this as a global variable? And if there is some other way to do it...

char scherm[35][67];

[itsme86]

What do you mean "you can't"? Have you tried or did you just hear somewhere that you can't? If you've tried, do you get an error? What does the error say? What operating system are you using? What compiler?

It's easier for us to help you if you tell us what it is doing.

There's no "C says you can't define a multidimensional array globally" if that's what you're looking for.

You might want to give this webpage a quick glance: http://www.catb.org/~esr/faqs/smart-questions.html

[LowLife]

Ok, I thought the error was common, but it seems not to be the case, so here is some more info:

I try to define a global two dimensional array called "screen" with f.e. 5 rows and 10 columns:

char screen[5][10];

when I try to compile my program using the build in Bloodshed Dev-C++ compiler, under Windows XP pro, it states the following error:

variable-size type declared outside of any function

excuse me if my questions are starting to bug you...

[itsme86]

Are you really you're giving constants for the dimension sizes? Or are you doing something more like:

char screen[height][width];

Please post the exact line of code that's causing the error.

[quzah]

You must not have been doing that exact line of code. Something like:

char screen[5][n];

is what it sounds like you were trying to do. The error you have is saying you're trying to declare a global array whose size is not known at compile time.

Does this compile:

char foo[5][10];
int main( void )
{
    return 0;
}

It should, with the possible warning about an unused variable. Other than that, it should compile error free.


Quzah.

[LowLife]

indeed, it's not the exact code, guess I'm trying to hard to keep my explanation simple, my apologies, this is what I really did:

int row = 5,
    column = 10;
char screen[row][column];

maybe this could solve it?

#define row 5
#define column 10
char screen[row][column];

[Quantum1024]

maybe this could solve it?

Did you compile and test this? As this would work

[SlyMaelstrom]

You can't declare an array's size outside of main with non-const variables. This is because, as Quzah said, you're trying to declare a global array whose size is not known at compile time.

Yes, your #define code would work and so would this.

const int row = 5;
const int column = 10;
char screen[row][column];

[LowLife]

I'm sticking with my #define code, since the thing the last post suggested:

const int row = 5;
const int column = 10;
char screen[row][column];

gives the same error: "variable-size type declared outside of any function"

[SlyMaelstrom]

Hmm... not on my compiler.

[itsme86]

Hmm... not on my compiler.

Then you should try compiling your C code as C instead of C++. const doesn't mean the same thing in both languages.

[SlyMaelstrom]

Ah, good call.

[dwks]

You can also use enums (my favorite):

enum {
    SIZE = 100
};

int array[SIZE];