Question

Please look at the below code snippet and let me know how the out comes out as 1 2 .

int[] a = { 1, 2, 3, 4 };
int[] b = { 2, 3, 1, 0 };
System.out.println( a [ (a = b)[3] ] );
System.out.println(a[0]);

Actual answer 1
2

Thanks

Answer 1

I’ll try to explain:

a [ (a = b)[3] ] will be executed in the following order:

1. a [...] – the array a will be read and the reference is stored for that
2. (a = b) – the variable a is set to reference array b
3. (a=b)[3] – the 4th element of array b is read (because of step 2) , the value is 0
4. a [ (a = b)[3] ] – this is now equal to a[0] (because of steps 1 and 3), the value is 1

a[0] now yields 2 since a references array b (because of step 2) and the first element in that array is 2.