Question

The following simplest Java code returns some unexpected output. Let’s look at it.

package interchange;

final public class Main
{
    public static void main(String[] args)
    {
        int x = 15;
        int y = 20;

        x^=y^=x^=y;
        System.out.println("x = " + x + "; y = " + y);
    }
}

---

The code above displays the following output on the console.

x = 0; y = 15

How?

Answer 1

According to operator precedence it can be rewritten like this

x^=y; // 15 ^ 20 = 27, x = 27
y^=27; // 20 ^ 27 = 15, y = 15
x^=15; // 15 ^ 15 = 0, x = 0