complex.java

复数类

//【习3.4】  复数类。

public class Complex
{
    private double real,im;                //实部，虚部

    public Complex(double real, double im) //构造方法
    {
        this.real = real;
        this.im = im;
    }
    
    public Complex(double real)            //构造方法重载
    {
        this(real,0);
    }
    
    public Complex()
    {
        this(0,0);
    }
    
    public Complex(Complex c)              //拷贝构造方法
    {
        this(c.real,c.im);
    }
    
    public boolean equals(Complex c)       //比较两个对象是否相等
    {
        return this.real==c.real && this.im==c.im;
    } 
    
    public String toString() 
    {
        return "("+this.real+"+"+this.im+"i)";
    }
    
    public void add(Complex c)             //两个对象相加
    {                                      //改变当前对象，没有返回新对象
        this.real += c.real;
        this.im += c.im;
    }
    
    public Complex plus(Complex c)         //两个对象相加，与add()方法参数一样不能重载
    {                                      //返回新创建对象，没有改变当前对象
        return new Complex(this.real+c.real, this.im+c.im);
    }
    
    public void subtract(Complex c)        //两个对象相减
    {                                      //改变当前对象，没有返回新对象
        this.real -= c.real;
        this.im -= c.im;
    }
    
    public Complex minus(Complex c)        //两个对象相减，与subtract()方法参数一样不能重载
    {                                      //返回新创建的对象，没有改变当前对象
        return new Complex(this.real-c.real, this.im-c.im);
    }
}


class Complex__ex
{
    public static void main(String args[])
    {
        Complex a = new Complex(1,2);
        Complex b = new Complex(3,5);
        Complex c = a.plus(b);             //返回新创建对象
        System.out.println(a+" + "+b+" = "+c);
    } 
}

/*
程序运行结果如下：
(1.0+2.0i) + (3.0+5.0i) = (40.0+7.0i)

*/