swap 2 variables without temp variable.

Scratch.java

class Scratch {
    public static void main(String[] args) {
        double a = -9, b = -11;
        System.out.println("a: " + a + "\nb: " + b);
        a = a * b;
        b = a/b;
        a = a/b;



        System.out.println("a: " + a + "\nb: " + b);


    }
}