class Complex {

定義實部、虛部;

構造方法定義;

四則運算方法定義，如加法可定義為：

public Complex add(Complex oper){....}

其它的成員

}

使用該類時，可以

Complex a = new Complex(3.0, 4.), b = new Complex(3.5, 4.5), c;

c = a.add(b);

System.out.println("c="+c);

public class Complex

{

private double realPart;

private double imaginaryPart;

public Complex(double a, double b)

{

this.realPart = a;

this.imaginaryPart = b;

}

public Complex add(Complex a)

{

Complex result = new Complex(this.realPart + a.realPart, this.imaginaryPart + a.imaginaryPart);//(why?)

return result;

}

public Complex decrease(Complex a)

{

Complex result = new Complex(this.realPart - a.realPart, this.imaginaryPart - a.imaginaryPart);//(why?)

return result;

}

public Complex multiply(Complex a)

{

double newReal = this.realPart*a.realPart - this.imaginaryPart * a.imaginaryPart;

double newImaginary = this.realPart*a.imaginaryPart + this.imaginaryPart * a.realPart;

Complex result = new Complex(newReal, newImaginary);

return result;

}

public Complex divide(Complex a)

{

Complex conjugate = new Complex(this.realPart, -this.imaginaryPart);

Complex multiplication = conjugate.multiply(a);

multiplication.realPart /= this.realPart*this.realPart + this.imaginaryPart * this.imaginaryPart;

multiplication.imaginaryPart /= this.realPart*this.realPart + this.imaginaryPart * this.imaginaryPart;

return multiplication;

}

public String toString()

{

String show = this.realPart + " + " + this.imaginaryPart + "i";

return show;

}

public static void main(String [] args)

{

Complex a = new Complex (2, 3);

Complex b = new Complex (1,1);

System.out.println((a.add(b)).toString());

System.out.println((a.decrease(b)).toString());

System.out.println((a.multiply(b)).toString());

System.out.println((a.divide(b)).toString());

}

}