复数相加+equels、hashcode、clone<一>

package com.jdk7.chapter1;

public class ComplexNumber {
    
    private double realPart;
    private double imagePart;
    
    public double getRealPart() {
        return realPart;
    }

    public void setRealPart(double realPart) {
        this.realPart = realPart;
    }

    public double getImagePart() {
        return imagePart;
    }

    public void setImagePart(double imagePart) {
        this.imagePart = imagePart;
    }

    @Override
    public String toString() {
        return "realPart=" + realPart + ", imagePart=" + imagePart + "i";
    }

    /**
     * 默认构造函数
     */
    public ComplexNumber(){
        this.realPart = 0.0;
        this.imagePart = 0.0;
    }
    
    /**
     * 自定义带参构造函数
     * @param a
     * @param b
     */
    public ComplexNumber(double a,double b){
        this.realPart = a;
        this.imagePart = b;
    }
    
    /**
     * 复数相加
     * 返回复数类型
     * @return
     */
    public ComplexNumber add(ComplexNumber comn){
        if(comn==null){
            System.err.println("对象不能为null");
            return new ComplexNumber();
        }else{
            return new ComplexNumber(this.realPart+comn.realPart,this.imagePart+comn.imagePart);
        }
    }
    
    public static void main(String[] args) {
        ComplexNumber a = new ComplexNumber(1,2);
//        ComplexNumber a = new ComplexNumber();
//        ComplexNumber a = null;
        ComplexNumber b = new ComplexNumber(1,2);
//        ComplexNumber b = new ComplexNumber();
//        ComplexNumber b = null;
        // 被加数不能为null
//        System.out.println("(a+b) = "+a.add(b).toString());
        
        //a和b的值虽然相同，但是在声明为类类型变量时为不同的内存地址，object提供的equels方法比较的是内存地址
        System.out.println("(a==b) : "+a.equals(b));    
        //对象实例内存地址不同，hashcode也不相同
        System.out.println("hashcode of a: "+a.hashCode());
        System.out.println("hashcode of b: "+b.hashCode());
        try {
            System.out.println(a.clone());
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        
    }

}