第八周任务一：运算符的重载

* (程序头部注释开始)
* 程序的版权和版本声明部分
* Copyright (c) 2011, 烟台大学计算机学院学生
* All rights reserved.
* 文件名称：
* 作者：吴瑕
* 完成日期： 2012年 04月 03日
* 版本号：

*对任务及求解方法的描述部分
* 输入描述：

定义一个复数类重载运算符+、‐、*、/，使之能用于复数的加减乘除。

（1）方案一：请用类的成员函数完成运算符的重载；

#include<iostream>   
using namespace std; 
class Complex
{
public:
	Complex(){real=0;imag=0;}
	Complex(double r,double i){real=r;imag=i;}
	Complex operator+(Complex &c2);
	Complex operator-(Complex &c2);
	Complex operator*(Complex &c2);
	Complex operator/(Complex &c2);
	void display();
private:
	double real;
	double imag;
};
//下面定义成员函数

Complex Complex::operator+(Complex &c2)
{
	Complex c1;
	c1.real=real+c2.real;
	c1.imag=imag+c2.imag;
	return c1;

}
Complex Complex::operator-(Complex &c2)
{
	Complex c1;
	c1.real=real-c2.real;
	c1.imag=imag-c2.imag;
	return c1;

}
Complex Complex::operator*(Complex &c2)
{
	Complex c;  
	c.real=real*c2.real-imag*c2.imag;  
	c.imag=real*c2.imag+imag*c2.real; 
	return c;  
}
Complex Complex::operator/(Complex &c2)
{
	Complex c;  
	c.real=(real*(c2.real)+imag*c2.imag)/((c2.imag*c2.imag)+real*real);  
	c.imag=(imag*c2.real-real*c2.imag)/((c2.imag*c2.imag)+real*real);   
	return c;  
}
void Complex::display()
{
	cout<<"("<<real<<","<<imag<<"i)"<<endl;  
}

int main()
{
	Complex c1(3,4),c2(5,-10),c3;
	cout<<"c1=";
	c1.display();
	cout<<"c2=";
	c2.display();
	c3=c1+c2;
	cout<<"c1+c2=";
	c3.display();
	c3=c1-c2;
	cout<<"c1-c2=";
	c3.display();
	c3=c1*c2;
	cout<<"c1*c2=";
	c3.display();
	c3=c1/c2;
	cout<<"c1/c2=";
	c3.display();
	system("pause");
	return 0;
}

运行结果：

（2）方案二：请用类的友元函数，而不是成员函数，完成上面提及的运算符的重载；
#include<iostream>   
using namespace std; 
class Complex
{
public:
	Complex(){real=0;imag=0;}
	Complex(double r,double i){real=r;imag=i;}
	friend Complex operator+(Complex c1,Complex &c2);
	friend Complex operator-(Complex c1,Complex &c2);
	friend Complex operator*(Complex c1,Complex &c2);
	friend Complex operator/(Complex c1,Complex &c2);
	void display();
private:
	double real;
	double imag;
};
//下面定义成员函数

Complex operator+(Complex c1,Complex &c2)
{
	Complex c;
	c.real=c1.real+c2.real;
	c.imag=c1.imag+c2.imag;
	return c;

}
Complex operator-(Complex c1,Complex &c2)
{
	Complex c;
	c.real=c1.real-c2.real;
	c.imag=c1.imag-c2.imag;
	return c;

}
Complex operator*(Complex c1,Complex &c2)
{
	Complex c;  
	c.real=c1.real*c2.real-c1.imag*c2.imag;  
	c.imag=c1.real*c2.imag+c1.imag*c2.real; 
	return c;  
}
Complex operator/(Complex c1,Complex &c2)
{
	Complex c;  
	c.real=(c1.real*(c2.real)+c1.imag*c2.imag)/((c2.imag*c2.imag)+c1.real*c1.real);  
	c.imag=(c1.imag*c2.real-c1.real*c2.imag)/((c2.imag*c2.imag)+c1.real*c1.real);   
	return c;  
}
void Complex::display()
{
	cout<<"("<<real<<","<<imag<<"i)"<<endl;  
}

int main()
{
	Complex c1(3,4),c2(5,-10),c3;
	cout<<"c1=";
	c1.display();
	cout<<"c2=";
	c2.display();
	c3=c1+c2;
	cout<<"c1+c2=";
	c3.display();
	c3=c1-c2;
	cout<<"c1-c2=";
	c3.display();
	c3=c1*c2;
	cout<<"c1*c2=";
	c3.display();
	c3=c1/c2;
	cout<<"c1/c2=";
	c3.display();
	system("pause");
	return 0;
}





运行结果：


（3）方案三：在方案二的基础上，扩展+、‐、*、/运算符的功能，使之能与double 型数据进行运算。
设Complex c; double d; c?d 和d?c 的结果为“将d 视为实部为d 的复数同c 运算”的结果（其中?为+、
‐、*、/之一）。另外，再定义一目运算符 ‐，‐c 相当于0‐c。
 
#include<iostream>   
using namespace std; 
class Complex
{
public:
	Complex(){real=0;imag=0;}
	Complex(double r,double i){real=r;imag=i;}
	friend Complex operator+(Complex c1,Complex &c2);
	friend Complex operator-(Complex c1,Complex &c2);
	friend Complex operator*(Complex c1,Complex &c2);
	friend Complex operator/(Complex c1,Complex &c2);
	friend Complex operator+(Complex c1,double d);
	friend Complex operator-(Complex c1,double d);
	friend Complex operator*(Complex c1,double d);
	friend Complex operator/(Complex c1,double d);
	friend Complex operator-(Complex c1);
	void display();
private:
	double real;
	double imag;
};
//下面定义成员函数
Complex operator+(Complex c1,Complex &c2)
{
	Complex c;
	c.real=c1.real+c2.real;
	c.imag=c1.imag+c2.imag;
	return c;

}
Complex operator-(Complex c1,Complex &c2)
{
	Complex c;
	c.real=c1.real-c2.real;
	c.imag=c1.imag-c2.imag;
	return c;

}
Complex operator*(Complex c1,Complex &c2)
{
	Complex c;  
	c.real=c1.real*c2.real-c1.imag*c2.imag;  
	c.imag=c1.real*c2.imag+c1.imag*c2.real; 
	return c;  
}
Complex operator/(Complex c1,Complex &c2)
{
	Complex c;  
	c.real=(c1.real*(c2.real)+c1.imag*c2.imag)/((c2.imag*c2.imag)+c1.real*c1.real);  
	c.imag=(c1.imag*c2.real-c1.real*c2.imag)/((c2.imag*c2.imag)+c1.real*c1.real);   
	return c;  
}

Complex operator+(Complex c1,double d)
{
	Complex c;
	c.real=c1.real+d;
	c.imag=c1.imag;
	return c;

}
Complex operator-(Complex c1,double d)
{
	Complex c;
	c.real=c1.real-d;
	c.imag=c1.imag;
	return c;

}
Complex operator*(Complex c1,double d)
{
	Complex c;  
	c.real=c1.real*d;  
	c.imag=c1.imag*d;  
	return c;  
}
Complex operator/(Complex c1,double d)
{
	Complex c;  
	c.real=c1.real/d;  
	c.imag=c1.imag/d;  
	return c;  
}
void Complex::display()
{
	cout<<"("<<real<<","<<imag<<"i)"<<endl;  
}

Complex operator-(Complex c1)
{
	Complex c;
	c.real=-c1.real;
	c.imag=-c1.imag;
	return c;
}
int main()
{
	Complex c1(3,4),c2(5,-10),c3;
	double d=5.1;

	cout<<"c1=";
	c1.display();
	cout<<"c2=";
	c2.display();
	c3=c1+c2;
	cout<<"c1+c2=";
	c3.display();

	c3=c1-c2;
	cout<<"c1-c2=";
	c3.display();

	c3=c1*c2;
	cout<<"c1*c2=";
	c3.display();

	c3=c1/c2;
	cout<<"c1/c2=";
	c3.display();

	c3=c1+d;
	cout<<"c1+d=";
	c3.display();

	c3=c1-d;
	cout<<"c1-d=";
	c3.display();

	c3=c1*d;
	cout<<"c1*d=";
	c3.display();

	c3=c1/d;
	cout<<"c1/d=";
	c3.display();

	c3=-c1;
	cout<<"-c1=";
	c3.display();

	system("pause");
	return 0;
}


运行结果：



上机感言：

运算符的重载实质上就是为某一要用的运算符赋予一定的功能，使其实现自己要实现的运算。运算符的重载可读性强！

在实现友元函数时括号内忘了该怎么正确书写，最后出了好多错误啊！不过我感觉它出的值，下次就记住了，不会再犯这样的错误了！