C++学习笔记（1）

先帖一个课堂作业，运算符重载、友元函数：

#include <iostream.h>

class Complex
{
private:
	double rel,img;
public:
	Complex(double r=0,double i=0)
	{
		rel=r;
		img=i;
	}
	void show(void)
	{
		cout<<rel;
		if(img>=0)cout<<"+";
		if(img)cout<<img<<"i";
		cout<<endl;
	};
	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);
};

Complex operator+(Complex &c1,Complex &c2)
{
	Complex c;
	c.rel = c1.rel+c2.rel;
	c.img = c1.img+c2.img;
	return c;
}
Complex operator-(Complex &c1,Complex &c2)
{
	Complex c;
	c.rel = c1.rel-c2.rel;
	c.img = c1.img-c2.img;
	return c;
}
Complex operator*(Complex &c1,Complex &c2)
{
	Complex c;
	c.rel = c1.rel*c2.rel-c1.img*c2.img;
	c.img = c1.img*c2.rel+c1.rel*c2.img;
	return c;
}
Complex operator/(Complex &c1,Complex &c2)
{
	Complex c;
	double temp;
	temp=c2.rel*c2.rel+c2.img*c2.img;
	if(temp)
	{
		c.rel = (c1.rel*c2.rel+c1.img*c2.img)/temp;
		c.img = (c1.img*c2.rel-c1.rel*c2.img)/temp;	
	}
	return c;
}

int main(int argc,int *argv[])
{
	Complex c1(1,2);
	Complex c2(3,4);
	Complex c3(0,0);
	c3=c1+c2;
	cout<<"c1+c2=";
	c3.show();
	c3=c1-c2;
	cout<<"c1-c2=";
	c3.show();
	c3=c1*c2;
	cout<<"c1*c2=";
	c3.show();
	c3=c1/c2;
	cout<<"c1/c2=";
	c3.show();
	return 0;
}