疑惑

[machaoqun6666]

#include <iostream>
class CFenshu
{
int fm,fz;
friend std::ostream & operator<<(ostream& out,const CFenshu& fs);
public
.....
};
std::ostream & operator<<(ostream& out,const CFenshu& fs)
{
out<<fs.fz<<"/"<<fs.fm;
return out;
}
友元为什么不对？
错误信息：declaration of'operator<<'as non-function
新手，请赐教。

[xkyx_cn]

#include <iostream>

using namespace std;

class CFenshu;
ostream & operator<<(ostream& out,const CFenshu& fs);

class CFenshu 
{ 
	int fm,fz;
public:
	friend ostream & operator<<(ostream& out,const CFenshu& fs);
};

ostream & operator<<(ostream& out,const CFenshu& fs) 
{ 
	out << fs.fz << "/" << fs.fm; 
	return out; 
}

int main()
{
	CFenshu fs;
	cout << fs << endl;

	return 0;
}

[lzr4304061988012]

#include <iostream> 
using namespace std;
  class CFenshu 
{ 
      int fm,fz; 
      friend std::ostream & operator <<(ostream& out,const CFenshu& fs); 
 
   
}; 
  std::ostream & operator <<(ostream& out,const CFenshu& fs) 
  { 
            out <<fs.fz <<"/" <<fs.fm; 
            return out; 
   } 

[zeroczh]

#include <iostream>

class CFenshu
{
int fm,fz;
friend std::ostream & operator <<(std::ostream& out,const CFenshu& fs);
public:
};

std::ostream & operator <<(std::ostream& out,const CFenshu& fs)
{
out <<fs.fz <<"/" <<fs.fm;
return out;
}

int main()
{
return 0;
}

[Maxwell]

class CFenshu
{
int fm,fz;
friend std::ostream& operator<<(std::ostream& out,const CFenshu& fs);
};

std::ostream& operator<<(std::ostream& out,const CFenshu& fs)
{
out <<fs.fz <<"/" <<fs.fm;
return out;
}

漏了红字部分。

[K行天下]

#include <iostream>
using namespace std;

[太乙]

[Quote=引用 5 楼 k2eats 的回复:]
#include <iostream>
using namespace std;
[/Quote]

有时还可以用
#include<iostream.h>

当然，还是上面那个好用！

[machaoqun6666]

非常感谢！