Can someone explain me this question

Question

What is output in this code:

int a = (1,2,3,4);
cout << a;

I have answered 1,2,3,4 and the correct answer is 4. Why?

Answer 1

comma operator evaluates left values and discrads results then returns right value

cout << (cout << 2, cout << 3, 4);
Output: 234
https://stackoverflow.com/q/52550/9132046

Answer 2

Thanks

Answer 3

Its not correct syntax for array,
I didn't get why they use simple brackets instead of curly braces

Answer 4

Valeti Naveen that's what confused me