谭浩强c++ 运算符重载编译有问题

[h_5_hao]

#include <iostream>
using namespace std;
class Complex
{
public:
friend ostream operator<<(ostream&os,Complex&c);

Complex(){real=0;imag=0;}
Complex(float r,float i):real(r),imag(i){}
Complex operator+(Complex&a)
{
Complex c;
c.real=real+a.real;
c.imag=imag+a.imag;
return c;
}

Complex operator-(Complex&a)
{
Complex c;
c.real=real-a.real;
c.imag=imag-a.imag;
return c;
}
float get_real(){return real;}
float get_imag(){return imag;}


private:
float real;
float imag;
};

ostream& operator<<(ostream&os,Complex&c )
{
os<<c.real<<'+'<<c.imag<<'i'<<endl;
return os;
}
int main()
{
Complex c1(15,42),c2(74,65),c3;
c3=c1-c2;
cout<<c3;

return 0;
}

[sagegz]

好了,LZ对照下吧.

#include <iostream> 

using namespace std; 
class Complex 
{ 
public: 
	friend ostream& operator <<(ostream& os,Complex &c);	//这里返回类型是ostream&
	Complex(){real=0;imag=0;} 
	Complex(float r,float i):real(r),imag(i){}
	Complex operator+(Complex &a) 
	{ 
		Complex c; 
		c.real=real+a.real; 
		c.imag=imag+a.imag; 
		return c; 
	}
	Complex operator-(Complex &a) 
	{ 
		Complex c; 
		c.real=real-a.real; 
		c.imag=imag-a.imag; 
		return c; 
	} 
	float get_real(){return real;} 
	float get_imag(){return imag;} 


	private: 
	float real; 
		float imag; 
}; 

ostream& operator <<(ostream &os,Complex &c ) 
{ 
	os <<c.real <<'+' <<c.imag <<'i' <<endl; 
	return os; 
} 
int main() 
{                                                                                                                                                                                                                                                                                                                                                          
	Complex c1(15,42),c2(74,65),c3; 
	c3=c1-c2; 
	cout <<c3;
	return 0;  
} 

[fairchild811]

class Complex
{
public:
friend ostream operator <<(ostream&os,Complex&c);

---->

class Complex
{
public:
friend ostream& operator <<(ostream&os,Complex&c);

[珍惜生命远离CPP]

friend ostream operator <<(ostream&os,Complex&c); 

改为

friend ostream& operator <<(ostream&os,Complex&c);

[猫已经找不回了]

ostream& operator < <(ostream&os,Complex&c ) //在类外，你不用标明类的作用域的？
{
os < <c.real < <'+' < <c.imag < <'i' < <endl;
return os;
}

[猫已经找不回了]

此外，如果你是VC6，friend函数的定义最好放在类体里，不然容易出错。

[xylicon]

#include <iostream> 
using namespace std; 

class Complex; // 
ostream& operator<<(ostream& os,Complex& c);  // 必需在定义友元函数 friend ostream& operator<< 之前声明该函数

class Complex 
{ 
public: 
	friend ostream& operator<<(ostream& os,Complex& c); // 这里返回类型应该是ostream&
	
	Complex(){real=0;imag=0;} 
	Complex(float r,float i):real(r),imag(i){} 
    Complex operator+(Complex&a) 
	{ 
		Complex c; 
		c.real=real+a.real; 
		c.imag=imag+a.imag; 
		return c; 
	} 
	
	Complex operator-(Complex&a) 
	{ 
		Complex c; 
		c.real=real-a.real; 
		c.imag=imag-a.imag; 
		return c; 
	} 
	float get_real(){return real;} 
	float get_imag(){return imag;} 
	
	
private: 
	float real; 
    float imag; 
}; 

ostream& operator<<(ostream& os, Complex& c) 
{ 
	os << c.real <<'+' << c.imag <<'i' << endl; 
	return os; 
} 


int main() 
{                                                                                                              
    Complex c1(15,42),c2(74,65),c3; 
	c3=c1-c2; 
	cout << c3; 
	
	return 0;  
} 

[h_5_hao]

谢谢大家了 呵呵~

[ytzxj]

friend ostream operator < <(ostream&os,Complex&c);
ostream& operator < <(ostream&os,Complex&c )
{
os < <c.real < <'+' < <c.imag < <'i' < <endl;
return os;
}
根本不相配，