Does int a[]{}; is a empty array?

Answer 1

if you mean
int a[]={};
answer is yes

Answer 2

int a[]{};

initializes an array a of size 0 storing no elements.

Note that this is list initialization, which is a valid syntax for for initializing arrays, e.g.

int arr[] = {1,2,3};
int arr2[]{1,2,3};

http://en.cppreference.com/w/cpp/language/list_initialization#Explanation

Answer 3

Martin Taylor Ah, thanks. I've just read an article on how list initialization may be useful, though. Turns out it might not just be a shorthand, but I may be wrong. Of course, conflicting views are also present. Thoughts?

https://stackoverflow.com/questions/18222926/why-is-list-initialization-using-curly-braces-better-than-the-alternatives

Answer 4

The array needs to be declared first.
Try:
int [] a = new int[10];

This array will be declared as an array capable of storing up to 10 elements.