Incrementor logic

Question

I\'m trying to get deeper with post and pre incrementors but am a bit stuck with the following expression :

public static void main(String[] args) {
    int i         


        

Answer 1

I suggest the following: format the code differently, so that there's only 1 statement per line, e.g.

@Test
public void test() {
    int i = 0;
    i = 
    i+=
    (
    ++i 
    + 
    (
    i+=
    2 
    + 
    --i
    ) 
    -
    ++i
    );
    System.out.println(i); // Prints 0 instead of 5
}

Then run it under the debugger and press F5 ("Step into") always. This will help you to understand in which order items get evaluated:

1. int i=0;
2. i=: ... (needs to wait for result of calculation A)
3. i+= ... (needs to wait B)
4. ++i: i=1
5. i+= ... (needs to wait C)
6. 2+
7. --i: i=0
8. ...: i=3 (result for wait C)
9. -
10. ++i: i=4 and operand of - is also 4
11. ...: i=0 (result for wait B)
12. ...: i=0 (result for wait A)

Line 10 will always make the result of line 3 0, so the initial value of i will never be changed by the whole operation.