Help with understanding this code (Java)

Question

I can't figure out why the output is
0
0
3
0
1

public class Program
{
public static void main(String[] args) {
int[] a = {1,2,3,4,1};
for(int n : a)
a[n] = 0;

for(int n : a)
System.out.println(n);
}
}

Answer 1

In line a[n]=0 you are using array values as index.
Step 1:
n=1 (first value in array)
a[1]=0
array: [1, 0, 3, 4, 1]
Step 2:
n=0 (2 was replaced by 0 in step 1)
a[0]=0
array:[0, 0, 3, 4, 1]
Step 3:
n=3
a[3]=0
array:[0, 0, 3, 0, 1]
And so on

Answer 2

Aleksandrs thanks now I understand