variably modified array at file scope in C

Question

I have some code like this:

static int a = 6;
static int b = 3;

static int Hello[a][b] =
{
    { 1,2,3},
    { 1,2,3},
    { 1,2,3},
    { 1,2,3},
    { 1,2,3},
    { 1,2,3}
};

but when I compile it, it says error:

variably modified 'Hello' at file scope

how could this happen? and how could I fix it?

Answer 1

You can not have static array which size is given as a variable

That's why constants should be #defined:

#define a 6

This way preprocessor will replace a with 6, making it valid declaration.