How the result is 20?

Question

What is the output of this code?
int i = 0;
for (; i < 5; i += 4) {
i = i * i;
}
printf ("%d", i);

Answer 1

i = 0
i = 0*0 = 0
i += 4 = 4
i = 4 * 4 = 16
i += 4 = 20
print => 20