In what cases would it be useful to put a command within a Java for-loop update statement? [closed]

Question

I found out yesterday that you can make a Java for-loop that looks like this

for (int j = 0; j < myArray.length; System.out.println(j), j++ ) {

/* code */

}

This looks really unusual to me. When is coding like this acceptable/useful?

Answer 1

I would only ever do something like this if I had two loop variables, eg:

for(int i = 0, j = 10; i < 10 && j > 0; i++, j--) {
...
}

Apart from that, I would not recommend doing this as it obscures what the for loop is actually doing. It would be better to place any method calls with side effects inside the actual body.

Answer 2

This is equivalent to:

for (int j = 0; j < myArray.length; j++ ) {
  System.out.println(j);
}

I dont see any advantage of using it other than to trick students in the exam. It could be useful to check if student understands the functioning of for loop thoroughly.

Answer 3

You may also do it this way

for (int j = 0; j < myArray.length; System.out.println(j++)) {

}