第九周任务一

接第8周任务1，定义Complex类中的<<和>>运算符的重载，实现输入和输出，改造原程序中对运算结果显示方式，使程序读起来更自然。

#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);
	friend ostream& operator<<(ostream &, Complex &);
	friend istream& operator>>(istream &, Complex &);

private:
	double real;
	double imag;
};
//下面定义成员函数

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

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.real*c2.real+c2.imag*c2.imag);
	c.imag=(c2.real*imag-real*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
	return c;
}

ostream &operator<<(ostream & output, Complex &c)
{
	output << "(" << c.real ;
	if ( c.imag > 0 )
		output << "+" << c.imag << "i )" << endl;
	else
		output << c.imag << "i )" << endl;
	return output;
}

istream& operator>>(istream &input, Complex &c)
{
	char ch;
	cout << "请输入一个复数" << endl;
	while(1)
	{
		input >> c.real >> c.imag >> ch;
		if ( ch == 'i' )
			break;
		else
			cout<<"输入错误，请重新输入" << endl;
	}

	return input;
}


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

加上<< 和 >>的运算符，程序看起来更加简便、明了。。。