Why can't we use std::fill() the same way for 1D and 2D arrays? [migrated]

I have seen that if we have a 1D array int A[10], then to fill it with an arbitrary value, say 0, we use std::fill(A, A+10, 0)

For a 2D array B[10][10], we fill it with 0 as: std::fill(&B[0][0], &B[0][0] + sizeof(B), 0

However, I can't understand why we can not fill the 1D array A as: std::fill(&A[0], &A[0] + sizeof(A), 0

Can someone explain this?