The BCPL infix “!” operator makes it a bit clearer, I think:

    BCPL      C
    !a        *a
    a ! 0     a[0]
    0 ! a     0[a]
    !(a + 0)  *(a + 0)
    !(0 + a)  *(0 + a)

That’s where C got its 0-based semantics from—it would be a nasty surprise if 0 weren’t the identity for pointer addition!