Why is int x[n] wrong where n is a const value?

Question

I cannot understand why doing this is wrong:

const int n = 5; 
int x[n] = { 1,1,3,4,5 };

even though n is already a const valu

Answer 1

Why int x[n] is wrong where n is a const value?

n is not a constant. const only promise that n is a 'read-only' variable that shouldn't be modified during the program execution.
Note that in c, unlike c++, const qualified variables are not constant. Therefore, the array declared is a variable length array.
You can't use initializer list to initialize variable length arrays.

C11-§6.7.9/3:

The type of the entity to be initialized shall be an array of unknown size or a complete object type that is not a variable length array type.

You can use #define or enum to make n a constant

#define n 5
int x[n] = { 1,1,3,4,5 };