复数的四则运算
下面的代码是用Java编写的，主要是Complex的四则运算
该类主要负责实现复数的四则运算，加减乘除
每种运算都使用了两种方式，类似a+=b,c=a+b
减法使用加法表示，除法使用乘法表示，
包括取反，和取倒数
1.复数必须包含两个变量，实部（real）虚部（vir）,为方便外界调用，给予对应的Getter和Setter方法，同时，给予四种构造方法，无参，单参，双参，对象参
private double real;private double vir;public Complex() {}public Complex(double real) {this.real = real;}public Complex(double real, double vir) {this.real = real;this.vir = vir;}public Complex(Complex complex) {this(complex.real,complex.vir);}public double getReal() {return real;}public void setReal(double real) {this.real = real;}public double getVir() {return vir;}public void setVir(double vir) {this.vir = vir;}
2.为了实现减法用加法表示，除法用乘法表示，给出取反和取倒
鉴于这两个函数只是为完成减法和除法的编写，所以不打算给外界调用，故使用private
//取反private static Complex invert(Complex a) {return new Complex(-a.real,-a.vir);}/*取倒数 * 1/(a+bi) * (a-bi)/((a+bi)(a-bi)) * (a-bi)/(a*a + b*b) * 实部:a/(a*a + b*b)；虚部:-b/(a*a + b*b) */private static Complex reciprocal(Complex a) {if(a.real*a.real+a.vir*a.vir – 0 < 1e-6)throw new DivZeroException(“除0错”);//此处可直接抛RunTimeException()异常，DivZeroException()异常为我自行定义，继承了RunTimeException()return new Complex(a.real/(a.real*a.real+a.vir*a.vir),-(a.vir/(a.real*a.real+a.vir*a.vir)));}
3.每种四则运算皆有两种表示方式，类似a+=b,c=a+b,下面以加法为例
//a+=bpublic Complex add(Complex a) {this.real+=a.real;this.vir+=a.vir;return this;}//c=a+b,调用add(Complex a)public static Complex add(Complex a,Complex b) {return new Complex(a).add(b);}
4.重写equals方法和toString方法，输出格式为(real,vir)
@Overridepublic boolean equals(Object obj) {if (obj == null) {return false;}if (this == obj) {return true;}if (obj.getClass() != this.getClass()) {return false;}Complex c = (Complex) obj;return Math.abs(c.real – this.real) < 1e-6 && Math.abs(c.vir – this.vir) < 1e-6;}@Overridepublic String toString() {return “(“+real+”,”+vir+”)”;//用（real,vir）格式输出复数}
该类完整代码如下：
public class Complex {private double real;private double vir;public Complex() {}public Complex(double real) {this.real = real;}public Complex(double real, double vir) {this.real = real;this.vir = vir;}public Complex(Complex complex) {this(complex.real,complex.vir);}public double getReal() {return real;}public void setReal(double 香港vps real) {this.real = real;}public double getVir() {return vir;}public void setVir(double vir) {this.vir = vir;}//取反private static Complex invert(Complex a) {return new Complex(-a.real,-a.vir);}/*取倒数 * 1/(a+bi) * (a-bi)/((a+bi)(a-bi)) * (a-bi)/(a*a + b*b) * 实部:a/(a*a + b*b)；虚部:-b/(a*a + b*b) */private static Complex reciprocal(Complex a) {if(a.real*a.real+a.vir*a.vir – 0 < 1e-6)throw new DivZeroException(“除0错”);//此处可直接抛RunTimeException()异常，DivZeroException()异常为我自行定义，继承了RunTimeException()return new Complex(a.real/(a.real*a.real+a.vir*a.vir),-(a.vir/(a.real*a.real+a.vir*a.vir)));}//加法//a+=bpublic Complex add(Complex a) {this.real+=a.real;this.vir+=a.vir;return this;}//c=a+b,调用add(Complex a)public static Complex add(Complex a,Complex b) {return new Complex(a).add(b);}//减法//a-=bpublic Complex sub(Complex a) {return add(invert(a));}//c=a-bpublic static Complex sub(Complex a,Complex b) {return new Complex(a).add(invert(a));}//乘法//a*=b//实部：ac-bd 虚部:(ad+bc)ipublic Complex mul(Complex a) {double real1 = this.real;double real2 = a.real;double vir1 = this.vir;double vir2=a.vir;this.real = real1*real2-vir1*vir2;this.vir = real1*vir2+real2*vir1;return this;}//c=a*bpublic static Complex mul(Complex a,Complex b) {return new Complex(a).mul(b);}//a/=bpublic Complex div(Complex a) {return mul(reciprocal(a));}//c=a/bpublic static Complex div(Complex a,Complex b) {return new Complex(a).mul(reciprocal(b));}@Overridepublic boolean equals(Object obj) {if (obj == null) {return false;}if (this == obj) {return true;}if (obj.getClass() != this.getClass()) {return false;}Complex c = (Complex) obj;return Math.abs(c.real – this.real) < 1e-6 && Math.abs(c.vir – this.vir) < 1e-6;}//输出@Overridepublic String toString() {return “(“+real+”,”+vir+”)”;//用（real,vir）格式输出复数}}
下面为测试类，为了便于计算，只调用了双参的四则运算，即类似于c=a+b
在下面的测试类中，我使用Complex类直接调用了四则运算的方法，这种写法是可以的，但有一个前提，直接使用类名调用方法时，要求该方法为静态，即使用static修饰
public class Test {public static void main(String[] args) {Complex c1 = new Complex(1, -6);Complex c2 = new Complex(2, 6);System.out.println(“加法”);Complex c3 = Complex.add(c1, c2);System.out.println(c3);System.out.println(“减法”);Complex c4 =Complex.sub(c1, c2);System.out.println(c4);System.out.println(“乘法”);Complex c5 = Complex.mul(c1, c2);System.out.println(c5);System.out.println(“除法”);Complex c6 = Complex.div(c1, c2);System.out.println(c6);}}
不使用类名调用，add(Complex a,Complex b)就可以不使用“static”修饰。下面以加法为例，代码如下：
System.out.println(“加法”);Complex c3 = new Complex();c3.add(c1, c2);System.out.println(c3);
运行结果如下：
37217521
