what is space overhead (when referring to a c++ array)?

Question

I'm reading a lecture slide in my data structures class for arrays, but there is something that sort of confused me.

The example is in an array called x, defined as follows:

1-dimensional array x = [a, b, c, d] location(x[i]) = start + i

I'm not really understanding this, so could somebody explain this?

Answer 1

start is a variable, which holds address to the array. Since a pointer in 32-bit system has 4 bytes, it will occupy these four bytes. So if you want 4-byte array, you will actually need 8 bytes of memory: 4 for the array and another 4 for pointer to the first element of this array.