How to get array size for dynamic created memory

Question

Consider an example:

void main()
{
    int *arr;
    arr=new int[10];
}

How can I know the size of arr?

Answer 1

You have to keep track of it yourself. I'd recommend making life easier on yourself by using a vector or deque instead.

Answer 2

Two ways (please note that in the first arr is a ptr not an int):

int main()
{
    const int SIZE = 10;
    int* arr;
    arr = new int[SIZE];

    delete[] arr;
}

or better yet:

int main()
{
     std::vector<int> arr( 10 );
     std::size_t size = arr.size();
}