C++第9周项目1 - 实现复数类中的运算符重载

课程首页地址：http://blog.csdn.net/sxhelijian/article/details/7910565，本周题目链接：http://blog.csdn.net/sxhelijian/article/details/8841620

【项目1-Complex类】接第8周项目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。

参考解答：（在VS2008中调试通过，CodeBlocks中有编译错误，见后说明。）

#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 &c){real=c.real;imag=c.imag;return *this;}
	Complex operator-();
	//实现输入、输出的运算符重载
	friend ostream& operator<< (ostream& output, Complex& c);
	friend istream& operator>> (istream& input,Complex& c);
	//实现加减乘除的运算符重载
	friend Complex operator+(Complex &c1, Complex &c2);
	friend Complex operator+(double d1, Complex &c2);
	friend Complex operator+(Complex &c1, double d2);
	friend Complex operator-(Complex &c1, Complex &c2);
	friend Complex operator-(double d1, Complex &c2);
	friend Complex operator-(Complex &c1, double d2);
	friend Complex operator*(Complex &c1, Complex &c2);
	friend Complex operator*(double d1, Complex &c2);
	friend Complex operator*(Complex &c1, double d2);
	friend Complex operator/(Complex &c1, Complex &c2);
	friend Complex operator/(double d1, Complex &c2);
	friend Complex operator/(Complex &c1, double d2);
private:
	double real;
	double imag;
};

//实现输出的运算符重载
ostream &operator << (ostream &output, Complex &c)
{
    	output<<"("<<c.real;
	if(c.imag>=0) output<<"+";
	output<<c.imag<<"i)";
	return output;
}

//实现输入的运算符重载
istream& operator >> (istream& input,Complex& c)
{
    	int a,b;
	char sign,i;
	do
	{	cout<<"input a complex number(a+bi或a-bi):";
		input>>a>>sign>>b>>i;
	}
	while(!((sign=='+'||sign=='-')&&i=='i'));
	c.real=a;
	c.imag=(sign=='+')?b:-b;
	return input;
}

Complex Complex::operator-()
{
	return(0.0-*this);
}

//复数相加：(a+bi)+(c+di)=(a+c)+(b+d)i.
Complex operator+(Complex &c1, Complex &c2)
{
	Complex c;
	c.real=c1.real+c2.real;
	c.imag=c1.imag+c2.imag;
	return c;
}
Complex operator+(double d1, Complex &c2)
{
	Complex c0(d1,0),c;
	return c0+c2; //按运算法则计算的确可以，但充分利用已经定义好的代码，既省人力，也避免引入新的错误，但可能机器的效率会不佳
}
Complex operator+(Complex &c1, double d2)
{
	Complex c0(d2,0),c;
	c=c1+c0;
	return c;
}
//复数相减：(a+bi)-(c+di)=(a-c)+(b-d)i.
Complex operator-(Complex &c1, Complex &c2)
{
	Complex c;
	c.real=c1.real-c2.real;
	c.imag=c1.imag-c2.imag;
	return c;
}
Complex operator-(double d1, Complex &c2)
{
	Complex c(d1,0);
	return c-c2;
}
Complex operator-(Complex &c1, double d2)
{
	Complex c(d2,0);
	return c1-c;
}

//复数相乘：(a+bi)(c+di)=(ac－bd)+(bc+ad)i.
Complex operator*(Complex &c1, Complex &c2)
{
	Complex c;
	c.real=c1.real*c2.real-c1.imag*c2.imag;
	c.imag=c1.imag*c2.real+c1.real*c2.imag;
	return c;
}
Complex operator*(double d1, Complex &c2)
{
	Complex c(d1,0);
	return c*c2;
}
Complex operator*(Complex &c1, double d2)
{
	Complex c(d2,0);
	return c1*c;
}

//复数相除：(a+bi)/(c+di)=(ac+bd)/(c^2+d^2) +(bc-ad)/(c^2+d^2)i
Complex operator/(Complex &c1, Complex &c2)
{
	Complex c;
	c.real=(c1.real*c2.real+c1.imag*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
	c.imag=(c1.imag*c2.real-c1.real*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
	return c;
}
Complex operator/(double d1, Complex &c2)
{
	Complex c(d1,0);
	return c/c2;
}

Complex operator/(Complex &c1, double d2)
{
	Complex c(d2,0);
	return c1/c;
}

int main()
{
	Complex c1,c2,c3,c;
	double d=11;
	cout<<"c1: "<<endl;;
	cin>>c1;
	cout<<"c2: "<<endl;
	cin>>c2;
	cout<<"c1="<<c1<<endl;
	cout<<"c2="<<c2<<endl;
	cout<<"d="<<d<<endl;
	cout<<"-c1="<<(-c1);
	c3=c1+c2;
	cout<<"c1+c2="<<c3<<endl;
	cout<<"c1+d="<<(c1+d)<<endl;
	cout<<"d+c1="<<(d+c1)<<endl;
	c3=c1-c2;
	cout<<"c1-c2="<<c3<<endl;
	cout<<"c1-d="<<(c1-d)<<endl;
	cout<<"d-c1="<<(d-c1)<<endl;
	c3=c1*c2;
	cout<<"c1*c2="<<c3<<endl;
	cout<<"c1*d="<<(c1*d)<<endl;
	cout<<"d*c1="<<(d*c1)<<endl;
	c3=c1/c2;
	cout<<"c1/c2="<<c3<<endl;
	cout<<"c1/d="<<(c1/d)<<endl;
	cout<<"d/c1="<<(d/c1)<<endl;

	return 0;
}

　　CodeBlocks中有编译错误发生在第149、152、153、156、157、160、161、164、165行。146、147、151等直接输出复数类对象没有出问题，而问题出在了输出重载的运算结果的输出。这说明不是operator<<()重载有问题，如果将第149行写为：

cout<<"-c1=";
Complex c=-c1;
cout<<c;

　　问题解决，其他地方类似。

　　曾经怀疑是否是在复制构造函数上出现问题，但排除了这种可能。难道是CodeBlocks中编译器新版本中的新要求，不而知。先发在此处等读者在评价中指点吧。