Power of Two - Walkthrough

Let me trace $n = 16$:

$\bullet$ $n = 16$, $16 \bmod 2 = 0$, so $n$ becomes $8$

$\bullet$ $n = 8$, $8 \bmod 2 = 0$, so $n$ becomes $4$

$\bullet$ $n = 4$, $4 \bmod 2 = 0$, so $n$ becomes $2$

$\bullet$ $n = 2$, $2 \bmod 2 = 0$, so $n$ becomes $1$

$\bullet$ Loop exits, return true

Now try $n = 6$: $6 \bmod 2 = 0$, $n$ becomes $3$. Then $3 \bmod 2 = 1$, so return false immediately.