public static boolean divide() {
        if ( !popTwo() ) return false;
        if ( x == 0 ) {
            System.out.println("Cannot divide by 0.");
            calcStack.push(y);
            calcStack.push(x);
            return false;
        }
        else {
            double result = y / x;
            pushResult(result);
        }
        return true;
    }