public ComplexStruct Multi(ComplexStruct x)
        {
            ComplexStruct y;

            y.im = re * x.im + im * x.re;
            y.re = re * x.re - im * x.im;
            return(y);
        }
        public ComplexStruct Minus(ComplexStruct x)
        {
            ComplexStruct y;

            y.im = im - x.im;
            y.re = re - x.re;
            return(y);
        }
        public ComplexStruct Plus(ComplexStruct x)
        {
            ComplexStruct y;

            y.im = im + x.im;
            y.re = re + x.re;
            return(y);
        }