Why size of array declaration is not require?

Question

Is it possible without size of array declaration we can use it. It may occur like memory leak problem.

int arr[] = {11, 35, 62, 555, 989};
int sum = 0;

for (int x = 0; x < 5; x++) {
sum += arr[x];
}

cout << sum << endl;
//Outputs 1652

Answer 1

Array can be of any size, that's not the problem. For loop might be the issue if you loop it more times than there are elements.
You will need to determine the length of the array somehow dynamically. Check out the std::array and range for, for example.
https://stackoverflow.com/questions/20234898/correct-way-of-loop-through-the-c-arrays

Answer 2

I didn't understand it, can u elaborate your answer please.